Aim: unified POD, user more happy

This section is renamed to "Output format modifiers" to make it simple.

To make it even more simple, a subsection is added:
"reStructuredText only".

Other notes:
- paragraphing correction
- article correction
Signed-off-by: NTomasz Warniełło <tomasz.warniello@gmail.com>
Tested-by: NRandy Dunlap <rdunlap@infradead.org>
Acked-by: NRandy Dunlap <rdunlap@infradead.org>
Disliked-by: NAkira Yokosawa <akiyks@gmail.com>
Link: https://lore.kernel.org/r/20220218181628.1411551-6-tomasz.warniello@gmail.comSigned-off-by: NJonathan Corbet <corbet@lwn.net>