docs: ftrace: fix a few formatting issues

Make sure that literal * characters are not interpreted as emphasis
markers.

Signed-off-by: Jonathan Corbet <corbet@lwn.net>
diff --git a/Documentation/trace/ftrace.rst b/Documentation/trace/ftrace.rst
index 636aa9bf..0bc33ad4 100644
--- a/Documentation/trace/ftrace.rst
+++ b/Documentation/trace/ftrace.rst
@@ -2615,13 +2615,13 @@
 
 Perhaps this is not enough. The filters also allow glob(7) matching.
 
-  <match>*
+  ``<match>*``
 	will match functions that begin with <match>
-  *<match>
+  ``*<match>``
 	will match functions that end with <match>
-  *<match>*
+  ``*<match>*``
 	will match functions that have <match> in it
-  <match1>*<match2>
+  ``<match1>*<match2>``
 	will match functions that begin with <match1> and end with <match2>
 
 .. note::