docs: Update Sphinx requirements

Commit f546ff0c0c07 ("Move our minimum Sphinx version to 1.7") raised
the minimum version to 1.7.

For pdfdocs, sphinx_pre_install says:

    note: If you want pdf, you need at least Sphinx 2.4.4.

, and current requirements.txt installs Sphinx 2.4.4.

Update Sphinx versions mentioned in docs and remove a note on earlier
Sphinx versions.

Update zh_CN and it_IT translations as well.

Signed-off-by: Akira Yokosawa <akiyks@gmail.com>
Cc: Federico Vaga <federico.vaga@vaga.pv.it>
Cc: Alex Shi <alexs@kernel.org>
Reviewed-by: Alex Shi <alexs@kernel.org>
Signed-off-by: Jonathan Corbet <corbet@lwn.net>
diff --git a/Documentation/doc-guide/sphinx.rst b/Documentation/doc-guide/sphinx.rst
index ec3e71f..e445cb1 100644
--- a/Documentation/doc-guide/sphinx.rst
+++ b/Documentation/doc-guide/sphinx.rst
@@ -27,7 +27,7 @@
 ==============
 
 The ReST markups currently used by the Documentation/ files are meant to be
-built with ``Sphinx`` version 1.3 or higher.
+built with ``Sphinx`` version 1.7 or higher.
 
 There's a script that checks for the Sphinx requirements. Please see
 :ref:`sphinx-pre-install` for further details.
@@ -43,10 +43,6 @@
 
 .. note::
 
-   #) Sphinx versions below 1.5 don't work properly with Python's
-      docutils version 0.13.1 or higher. So, if you're willing to use
-      those versions, you should run ``pip install 'docutils==0.12'``.
-
    #) It is recommended to use the RTD theme for html output. Depending
       on the Sphinx version, it should be installed separately,
       with ``pip install sphinx_rtd_theme``.
@@ -55,13 +51,13 @@
       those expressions are written using LaTeX notation. It needs texlive
       installed with amsfonts and amsmath in order to evaluate them.
 
-In summary, if you want to install Sphinx version 1.7.9, you should do::
+In summary, if you want to install Sphinx version 2.4.4, you should do::
 
-       $ virtualenv sphinx_1.7.9
-       $ . sphinx_1.7.9/bin/activate
-       (sphinx_1.7.9) $ pip install -r Documentation/sphinx/requirements.txt
+       $ virtualenv sphinx_2.4.4
+       $ . sphinx_2.4.4/bin/activate
+       (sphinx_2.4.4) $ pip install -r Documentation/sphinx/requirements.txt
 
-After running ``. sphinx_1.7.9/bin/activate``, the prompt will change,
+After running ``. sphinx_2.4.4/bin/activate``, the prompt will change,
 in order to indicate that you're using the new environment. If you
 open a new shell, you need to rerun this command to enter again at
 the virtual environment before building the documentation.
@@ -81,7 +77,7 @@
 PDF and LaTeX builds
 --------------------
 
-Such builds are currently supported only with Sphinx versions 1.4 and higher.
+Such builds are currently supported only with Sphinx versions 2.4 and higher.
 
 For PDF and LaTeX output, you'll also need ``XeLaTeX`` version 3.14159265.
 
@@ -104,8 +100,8 @@
 	You should run:
 
 		sudo dnf install -y texlive-luatex85
-		/usr/bin/virtualenv sphinx_1.7.9
-		. sphinx_1.7.9/bin/activate
+		/usr/bin/virtualenv sphinx_2.4.4
+		. sphinx_2.4.4/bin/activate
 		pip install -r Documentation/sphinx/requirements.txt
 
 	Can't build as 1 mandatory dependency is missing at ./scripts/sphinx-pre-install line 468.
diff --git a/Documentation/process/changes.rst b/Documentation/process/changes.rst
index e35ab74..b398b85 100644
--- a/Documentation/process/changes.rst
+++ b/Documentation/process/changes.rst
@@ -54,7 +54,7 @@
 iptables               1.4.2            iptables -V
 openssl & libcrypto    1.0.0            openssl version
 bc                     1.06.95          bc --version
-Sphinx\ [#f1]_	       1.3		sphinx-build --version
+Sphinx\ [#f1]_         1.7              sphinx-build --version
 ====================== ===============  ========================================
 
 .. [#f1] Sphinx is needed only to build the Kernel documentation
diff --git a/Documentation/translations/it_IT/doc-guide/sphinx.rst b/Documentation/translations/it_IT/doc-guide/sphinx.rst
index 0046d75..9762452 100644
--- a/Documentation/translations/it_IT/doc-guide/sphinx.rst
+++ b/Documentation/translations/it_IT/doc-guide/sphinx.rst
@@ -35,7 +35,7 @@
 ====================
 
 I marcatori ReST utilizzati nei file in Documentation/ sono pensati per essere
-processati da ``Sphinx`` nella versione 1.3 o superiore.
+processati da ``Sphinx`` nella versione 1.7 o superiore.
 
 Esiste uno script che verifica i requisiti Sphinx. Per ulteriori dettagli
 consultate :ref:`it_sphinx-pre-install`.
@@ -53,11 +53,6 @@
 
 .. note::
 
-   #) Le versioni di Sphinx inferiori alla 1.5 non funzionano bene
-      con il pacchetto Python docutils versione 0.13.1 o superiore.
-      Se volete usare queste versioni, allora dovere eseguire
-      ``pip install 'docutils==0.12'``.
-
    #) Viene raccomandato l'uso del tema RTD per la documentazione in HTML.
       A seconda della versione di Sphinx, potrebbe essere necessaria
       l'installazione tramite il comando ``pip install sphinx_rtd_theme``.
@@ -67,13 +62,13 @@
       utilizzando LaTeX. Per una corretta interpretazione, è necessario aver
       installato texlive con i pacchetti amdfonts e amsmath.
 
-Riassumendo, se volete installare la versione 1.7.9 di Sphinx dovete eseguire::
+Riassumendo, se volete installare la versione 2.4.4 di Sphinx dovete eseguire::
 
-       $ virtualenv sphinx_1.7.9
-       $ . sphinx_1.7.9/bin/activate
-       (sphinx_1.7.9) $ pip install -r Documentation/sphinx/requirements.txt
+       $ virtualenv sphinx_2.4.4
+       $ . sphinx_2.4.4/bin/activate
+       (sphinx_2.4.4) $ pip install -r Documentation/sphinx/requirements.txt
 
-Dopo aver eseguito ``. sphinx_1.7.9/bin/activate``, il prompt cambierà per
+Dopo aver eseguito ``. sphinx_2.4.4/bin/activate``, il prompt cambierà per
 indicare che state usando il nuovo ambiente. Se aprite un nuova sessione,
 prima di generare la documentazione, dovrete rieseguire questo comando per
 rientrare nell'ambiente virtuale.
@@ -94,7 +89,7 @@
 --------------------------
 
 Al momento, la generazione di questi documenti è supportata solo dalle
-versioni di Sphinx superiori alla 1.4.
+versioni di Sphinx superiori alla 2.4.
 
 Per la generazione di PDF e LaTeX, avrete bisogno anche del pacchetto
 ``XeLaTeX`` nella versione 3.14159265
@@ -119,8 +114,8 @@
 	You should run:
 
 		sudo dnf install -y texlive-luatex85
-		/usr/bin/virtualenv sphinx_1.7.9
-		. sphinx_1.7.9/bin/activate
+		/usr/bin/virtualenv sphinx_2.4.4
+		. sphinx_2.4.4/bin/activate
 		pip install -r Documentation/sphinx/requirements.txt
 
 	Can't build as 1 mandatory dependency is missing at ./scripts/sphinx-pre-install line 468.
diff --git a/Documentation/translations/it_IT/process/changes.rst b/Documentation/translations/it_IT/process/changes.rst
index 87d0818..dc71933 100644
--- a/Documentation/translations/it_IT/process/changes.rst
+++ b/Documentation/translations/it_IT/process/changes.rst
@@ -57,7 +57,7 @@
 iptables               1.4.2              iptables -V
 openssl & libcrypto    1.0.0              openssl version
 bc                     1.06.95            bc --version
-Sphinx\ [#f1]_         1.3                sphinx-build --version
+Sphinx\ [#f1]_         1.7                sphinx-build --version
 ====================== =================  ========================================
 
 .. [#f1] Sphinx è necessario solo per produrre la documentazione del Kernel
diff --git a/Documentation/translations/zh_CN/doc-guide/sphinx.rst b/Documentation/translations/zh_CN/doc-guide/sphinx.rst
index 951595c..23eac67 100644
--- a/Documentation/translations/zh_CN/doc-guide/sphinx.rst
+++ b/Documentation/translations/zh_CN/doc-guide/sphinx.rst
@@ -26,7 +26,7 @@
 安装Sphinx
 ==========
 
-Documentation/ 下的ReST文件现在使用sphinx1.3或更高版本构建。
+Documentation/ 下的ReST文件现在使用sphinx1.7或更高版本构建。
 
 这有一个脚本可以检查Sphinx的依赖项。更多详细信息见
 :ref:`sphinx-pre-install_zh` 。
@@ -40,22 +40,19 @@
 
 .. note::
 
-   #) 低于1.5版本的Sphinx无法与Python的0.13.1或更高版本docutils一起正常工作。
-      如果您想使用这些版本,那么应该运行 ``pip install 'docutils==0.12'`` 。
-
    #) html输出建议使用RTD主题。根据Sphinx版本的不同,它应该用
       ``pip install sphinx_rtd_theme`` 单独安装。
 
    #) 一些ReST页面包含数学表达式。由于Sphinx的工作方式,这些表达式是使用 LaTeX
       编写的。它需要安装amsfonts和amsmath宏包,以便显示。
 
-总之,如您要安装Sphinx 1.7.9版本,应执行::
+总之,如您要安装Sphinx 2.4.4版本,应执行::
 
-       $ virtualenv sphinx_1.7.9
-       $ . sphinx_1.7.9/bin/activate
-       (sphinx_1.7.9) $ pip install -r Documentation/sphinx/requirements.txt
+       $ virtualenv sphinx_2.4.4
+       $ . sphinx_2.4.4/bin/activate
+       (sphinx_2.4.4) $ pip install -r Documentation/sphinx/requirements.txt
 
-在运行 ``. sphinx_1.7.9/bin/activate`` 之后,提示符将变化,以指示您正在使用新
+在运行 ``. sphinx_2.4.4/bin/activate`` 之后,提示符将变化,以指示您正在使用新
 环境。如果您打开了一个新的shell,那么在构建文档之前,您需要重新运行此命令以再
 次进入虚拟环境中。
 
@@ -71,7 +68,7 @@
 PDF和LaTeX构建
 --------------
 
-目前只有Sphinx 1.4及更高版本才支持这种构建。
+目前只有Sphinx 2.4及更高版本才支持这种构建。
 
 对于PDF和LaTeX输出,还需要 ``XeLaTeX`` 3.14159265版本。(译注:此版本号真实
 存在)
@@ -93,8 +90,8 @@
 	You should run:
 
 		sudo dnf install -y texlive-luatex85
-		/usr/bin/virtualenv sphinx_1.7.9
-		. sphinx_1.7.9/bin/activate
+		/usr/bin/virtualenv sphinx_2.4.4
+		. sphinx_2.4.4/bin/activate
 		pip install -r Documentation/sphinx/requirements.txt
 
 	Can't build as 1 mandatory dependency is missing at ./scripts/sphinx-pre-install line 468.