docs: vm/page_owner: use literal blocks for param description

Sphinx generates hard-to-read lists of parameters at the bottom of the
page.  Fix them by putting literal-block markers of "::" in front of
them.

Link: https://lkml.kernel.org/r/cfd3bcc0-b51d-0c68-c065-ca1c4c202447@gmail.com
Signed-off-by: Akira Yokosawa <akiyks@gmail.com>
Fixes: 57f2b54 ("Documentation/vm/page_owner.rst: update the documentation")
Cc: Shenghong Han <hanshenghong2019@email.szu.edu.cn>
Cc: Haowen Bai <baihaowen@meizu.com>
Cc: Jonathan Corbet <corbet@lwn.net>
Cc: Alex Shi <seakeel@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

Author: akiyks

Documentation/vm/page_owner.rst

@@ -110,7 +110,7 @@ Usage
    If you want to sort by the page nums of buf, use the ``-m`` parameter.
    The detailed parameters are:
 
-   fundamental function:
+   fundamental function::
 
 	Sort:
 		-a		Sort by memory allocation time.
@@ -122,7 +122,7 @@ Usage
 		-s		Sort by stack trace.
 		-t		Sort by times (default).
 
-   additional function:
+   additional function::
 
 	Cull:
 		--cull <rules>
@@ -153,6 +153,7 @@ Usage
 
 STANDARD FORMAT SPECIFIERS
 ==========================
+::
 
 	KEY		LONG		DESCRIPTION
 	p		pid		process ID