admin-guide: Fix list formatting in tained-kernels.html

Without this patch, the points 1-9 in the list are rendered as an HTML
blockquote containing a list, causing them to be indented further than
the rest of the list.

While at it, also fix the quotation marks around G and P.
Signed-off-by: Jonathan Neuschäfer <j.neuschaefer@gmx.net>
Signed-off-by: Jonathan Corbet <corbet@lwn.net>

Documentation/admin-guide/tainted-kernels.rst

@@ -6,7 +6,7 @@ counter. This indicates that the kernel has been tainted by some
 mechanism.  The string is followed by a series of position-sensitive
 characters, each representing a particular tainted value.
 
-  1) 'G' if all modules loaded have a GPL or compatible license, 'P' if
+ 1)  ``G`` if all modules loaded have a GPL or compatible license, ``P`` if
      any proprietary module has been loaded.  Modules without a
      MODULE_LICENSE or with a MODULE_LICENSE that is not recognised by
      insmod as GPL compatible are assumed to be proprietary.