Help: More syntax highlighting for literal blocks

Covers almost all blocks containing actual code, except:

* Parsed-literal blocks can't be highlighted, including many command
  summaries and substitution-heavy docs like find_... commands.
  This is a Sphinx limitation.

* Code with errors, like CMP0049, DEPLOYMENT_ADDITIONAL_FILES,
  DEPLOYMENT_REMOTE_DIRECTORY, @PACKAGE_INIT@ substitution in the
  tutorial, bracket arguments/comments in cmake-language.7 and
  cmake-developer.7.

* FindQt4 module, which needs reformatting.

Modules/FindLua.cmake

@@ -29,13 +29,13 @@ This module defines:
 
 Note that the expected include convention is
 
-::
+.. code-block:: c
 
   #include "lua.h"
 
 and not
 
-::
+.. code-block:: c
 
   #include <lua/lua.h>