scripts: kernel-doc: Translate the "Output format selection modifier" subsection...

scripts: kernel-doc: Translate the "Output format selection modifier" subsection of OPTIONS

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: Tomasz Warniełło <tomasz.warniello@gmail.com>
Tested-by: Randy Dunlap <rdunlap@infradead.org>
Acked-by: Randy Dunlap <rdunlap@infradead.org>
Disliked-by: Akira Yokosawa <akiyks@gmail.com>
Link: https://lore.kernel.org/r/20220218181628.1411551-6-tomasz.warniello@gmail.com
Signed-off-by: Jonathan Corbet <corbet@lwn.net>