Incorrect filename for 'post_password_required' filter duplication inline docs

[coffee2code]

The canonical documentation for the 'post_password_required' filter is in post_password_required() in the file wp-includes/post-template.php.

That same function contains two duplicate uses of the filter, both of which are correctly documented as duplicates but incorrectly refer to the file wp-includes/post.php as containing the canonical documentation. Looks like this was incorrect when the filter was introduced in [38603].

The attached patch fixes the incorrect file references in the inline docs.

[coffee2code]

The patch mentioned in ticket description.

[SergeyBiryukov]

In 41567:

Docs: Correct filename references in duplicate hook comments for post_password_required filter.

Props coffee2code.
Fixes #41959.