Documentation/CodingStyle: replace underline markups

Sphinx doesn't accept underline markups by purpose.
While there are ways to support underline via CSS, this won't
be portable with non-html outputs.

As we want CodingStyle to do emphasis, replace _foo_ by **foo**,
using bold emphasis.

Signed-off-by: Mauro Carvalho Chehab <mchehab@s-opensource.com>
Signed-off-by: Jonathan Corbet <corbet@lwn.net>
diff --git a/Documentation/CodingStyle b/Documentation/CodingStyle
index c25528d..0024c36 100644
--- a/Documentation/CodingStyle
+++ b/Documentation/CodingStyle
@@ -2,7 +2,7 @@
 =========================
 
 This is a short document describing the preferred coding style for the
-linux kernel.  Coding style is very personal, and I won't _force_ my
+linux kernel.  Coding style is very personal, and I won't **force** my
 views on anybody, but this is what goes for anything that I have to be
 able to maintain, and I'd prefer it for most other things too.  Please
 at least consider the points made here.
@@ -136,10 +136,10 @@
 
 Heretic people all over the world have claimed that this inconsistency
 is ...  well ...  inconsistent, but all right-thinking people know that
-(a) K&R are _right_ and (b) K&R are right.  Besides, functions are
+(a) K&R are **right** and (b) K&R are right.  Besides, functions are
 special anyway (you can't nest them in C).
 
-Note that the closing brace is empty on a line of its own, _except_ in
+Note that the closing brace is empty on a line of its own, **except** in
 the cases where it is followed by a continuation of the same statement,
 ie a ``while`` in a do-statement or an ``else`` in an if-statement, like
 this:
@@ -283,10 +283,10 @@
 global variables are a must.  To call a global function ``foo`` is a
 shooting offense.
 
-GLOBAL variables (to be used only if you _really_ need them) need to
+GLOBAL variables (to be used only if you **really** need them) need to
 have descriptive names, as do global functions.  If you have a function
 that counts the number of active users, you should call that
-``count_active_users()`` or similar, you should _not_ call it ``cntusr()``.
+``count_active_users()`` or similar, you should **not** call it ``cntusr()``.
 
 Encoding the type of a function into the name (so-called Hungarian
 notation) is brain damaged - the compiler knows the types anyway and can
@@ -308,7 +308,7 @@
 -----------
 
 Please don't use things like ``vps_t``.
-It's a _mistake_ to use typedef for structures and pointers. When you see a
+It's a **mistake** to use typedef for structures and pointers. When you see a
 
 .. code-block:: c
 
@@ -327,7 +327,7 @@
 Lots of people think that typedefs ``help readability``. Not so. They are
 useful only for:
 
- (a) totally opaque objects (where the typedef is actively used to _hide_
+ (a) totally opaque objects (where the typedef is actively used to **hide**
      what the object is).
 
      Example: ``pte_t`` etc. opaque objects that you can only access using
@@ -335,15 +335,15 @@
 
      NOTE! Opaqueness and ``accessor functions`` are not good in themselves.
      The reason we have them for things like pte_t etc. is that there
-     really is absolutely _zero_ portably accessible information there.
+     really is absolutely **zero** portably accessible information there.
 
- (b) Clear integer types, where the abstraction _helps_ avoid confusion
+ (b) Clear integer types, where the abstraction **helps** avoid confusion
      whether it is ``int`` or ``long``.
 
      u8/u16/u32 are perfectly fine typedefs, although they fit into
      category (d) better than here.
 
-     NOTE! Again - there needs to be a _reason_ for this. If something is
+     NOTE! Again - there needs to be a **reason** for this. If something is
      ``unsigned long``, then there's no reason to do
 
 	typedef unsigned long myflags_t;
@@ -352,7 +352,7 @@
      might be an ``unsigned int`` and under other configurations might be
      ``unsigned long``, then by all means go ahead and use a typedef.
 
- (c) when you use sparse to literally create a _new_ type for
+ (c) when you use sparse to literally create a **new** type for
      type-checking.
 
  (d) New types which are identical to standard C99 types, in certain
@@ -381,7 +381,7 @@
 EVER use a typedef unless you can clearly match one of those rules.
 
 In general, a pointer, or a struct that has elements that can reasonably
-be directly accessed should _never_ be a typedef.
+be directly accessed should **never** be a typedef.
 
 
 6) Functions
@@ -509,7 +509,7 @@
 
 Comments are good, but there is also a danger of over-commenting.  NEVER
 try to explain HOW your code works in a comment: it's much better to
-write the code so that the _working_ is obvious, and it's a waste of
+write the code so that the **working** is obvious, and it's a waste of
 time to explain badly written code.
 
 Generally, you want your comments to tell WHAT your code does, not HOW.
@@ -656,14 +656,14 @@
 environment they are created and destroyed in should always have
 reference counts.  In the kernel, garbage collection doesn't exist (and
 outside the kernel garbage collection is slow and inefficient), which
-means that you absolutely _have_ to reference count all your uses.
+means that you absolutely **have** to reference count all your uses.
 
 Reference counting means that you can avoid locking, and allows multiple
 users to have access to the data structure in parallel - and not having
 to worry about the structure suddenly going away from under them just
 because they slept or did something else for a while.
 
-Note that locking is _not_ a replacement for reference counting.
+Note that locking is **not** a replacement for reference counting.
 Locking is used to keep data structures coherent, while reference
 counting is a memory management technique.  Usually both are needed, and
 they are not to be confused with each other.
@@ -719,7 +719,7 @@
 				return -EBUGGERED;	\
 		} while (0)
 
-is a _very_ bad idea.  It looks like a function call but exits the ``calling``
+is a **very** bad idea.  It looks like a function call but exits the ``calling``
 function; don't break the internal parsers of those who will read the code.
 
 2) macros that depend on having a local variable with a magic name: