favour of `elf_getshdrnum()`, `elf_getphdrnum()` and `elf_getshdrstrndx()`
respectively.
* Add new manual pages for `elf_getshdrstrndx()`, `elf_getphdrnum()` and
`elf_getshdrnum()`.
* Add a deprecation warning for `elf_getshstrndx()`, `elf_getphnum()` and
`elf_getshnum()`.
Obtained from: elftoolchain
MFC after: 1 month
Although groff_mdoc(7) gives another impression, this is the ordering
most widely used and also required by mdocml/mandoc.
Reviewed by: ru
Approved by: philip, ed (mentors)
- make document title match filename;
- remove hard sentence breaks, whitespace at EOL, and double whitespace;
- sort SEE ALSO xrefs, adding missing section numbers;
- fix a misspelled macro name.