tools/vm/page_owner_sort.c: fix comments

tools/vm/page_owner_sort.c: fix comments

Two adjustments are made:

1. Correct a grammatical error: replace the "what" in "Do the job what
   you want to debug" with "that".

2. Replace "has not been" with "has been" in the description of the -f
   option: According to Commit b1c9ba071e7d ("tools/vm/page_owner_sort.c:
   fix the instructions for use"), the description of the "-f" option is
   "Filter out the information of blocks whose memory has been released."

Link: https://lkml.kernel.org/r/20220301151438.166118-1-yejiajian2018@email.szu.edu.cn
Signed-off-by: Jiajian Ye <yejiajian2018@email.szu.edu.cn>
Cc: Stephen Rothwell <sfr@canb.auug.org.au>
Cc: Yinan Zhang <zhangyinan2019@email.szu.edu.cn>
Cc: Yixuan Cao <caoyixuan2019@email.szu.edu.cn>
Cc: Zhenliang Wei <weizhenliang@huawei.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>