docs: vm/page_owner: tweak literal block in STANDARD FORMAT SPECIFIERS

A semantic conflict between commit 5603f9bdea ("docs: vm/page_owner: use
literal blocks for param description") and a change queued for v5.19
authored by Jiajian Ye ("tools/vm/page_owner_sort.c: support sorting
blocks by multiple keys") results in a warning from "make htmldocs"
saying:

  [...]/vm/page_owner.rst:176: WARNING: Literal block expected; none found.

This is because a literal block in ReST ends at a line which has the same
indent as the paragraph preceding it.  In this case the one with no
indent.

Indent the two "For --xxxx option:" lines by two columns and make the
whole section a literal block.

While at it, fix indents by white spaces of "ator" keys.

Link: https://lkml.kernel.org/r/fdfecc82-d41e-6d8a-738d-4beb6faa27fb@gmail.com
Signed-of-by: Akira Yokosawa <akiyks@gmail.com>
Reported-by: Shenghong Han <hanshenghong2019@email.szu.edu.cn>
Cc: Jiajian Ye <yejiajian2018@email.szu.edu.cn>
Cc: Chongxi Zhao <zhaochongxi2019@email.szu.edu.cn>
Cc: Yinan Zhang <zhangyinan2019@email.szu.edu.cn>
Cc: Yixuan Cao <caoyixuan2019@email.szu.edu.cn>
Cc: Yongqiang Liu <liuyongqiang13@huawei.com>
Cc: Yuhong Feng <yuhongf@szu.edu.cn>
Cc: Haowen Bai <baihaowen@meizu.com>
Cc: Jonathan Corbet <corbet@lwn.net>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>

Documentation/vm/page_owner.rst

@@ -173,7 +173,7 @@ STANDARD FORMAT SPECIFIERS
 ==========================
 ::
 
-For --sort option:
+  For --sort option:
 
 	KEY		LONG		DESCRIPTION
 	p		pid		process ID
@@ -185,7 +185,7 @@ For --sort option:
 	at		alloc_ts	timestamp of the page when it was allocated
 	ator		allocator	memory allocator for pages
 
-For --curl option:
+  For --curl option:
 
 	KEY		LONG		DESCRIPTION
 	p		pid		process ID