Aim: unified POD, user more satisfied, script better structured

A subsection "reStructuredText only" is added for -enable-lineno.

Other notes:
- paragraphing 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/20220218181628.1411551-8-tomasz.warniello@gmail.comSigned-off-by: NJonathan Corbet <corbet@lwn.net>