Avoid method redefinitions in docs by using unique method names for internal hooks

[bpetty]

API documentation generators include all source files even if, in practice, only one of these files are included per request. Many core pages re-use the same method names for internal hooks which results in redefinitions for the docs, and resulting in missing documentation.

In general, it's good practice to keep these internal global method names as unique as possible anyway to avoid namespace (global scope) clashes since they aren't intended to be used as public API.

Patch coming soon...

[nacin]

I think we might need to keep display_header() in install.php, as that file can be running custom code via wp-content/install.php that could refer to it. Changing it in setup-config.php is simple enough, though. The rest looks fine.

[bpetty]

Updated patch leaves display_header() alone in wp-admin/install.php, but still changes the rest.

[SergeyBiryukov]

How about shorter names based on file names, e.g. options_reading_add_js()?

This would follow the same pattern as options_reading_blog_charset(), introduced in [21467].

[bpetty]

Not a bad idea, either way works for me.

[nacin]

In [21856]:

Rename duplicately defined internal functions (add_js, display_header) for documentation purposes. props bpetty, fixes #21564.