…y semicolon (#20172)

Follow-up to GH-19215

This header could not previously be used due to the `uriparser/Uri.h` include,
which is required for the struct definition. Since this struct is considered an
implementation detail, we can just make it opaque, preserving type safety, but
without allowing external users to touch its contents.

Fixes #19868.

…20239)

* PHP 8.5 | UPGRADING: fix entry about new grapheme $locale parameter

1. The `grapheme_levenshtein()` function is new to PHP 8.5, so the `$locale` parameter being added does not "change" the function (in the context of changes between PHP 8.4 and 8.5).
2. The `grapheme_substr()` function has also been given the new `$locale` parameter, but was not listed in the changelog entry.

Refs:
* https://wiki.php.net/rfc/grapheme_levenshtein
* bdcea11
* https://wiki.php.net/rfc/grapheme_add_locale_for_case_insensitive
* ad75c26

* NEWS: Add missing parentheses after `grapheme_substr`

Co-authored-by: tekimen <[email protected]>

* PHP-8.5:
  PHP 8.5 | UPGRADING: fix entry about new grapheme $locale parameter (#20239)
  uri: Make uri_parser_rfc3986.h usable for external extensions (#20173)
  Fix missing deprecation message for default case statement followed by semicolon (#20172)

The nightly matrix with an empty cache takes several hours to complete due to
the amount of jobs. This will effectively block the entire CI for the php
organization since there is an organization-wide limit of 20 jobs. Move the
cache buster job to Sunday to make it less likely for folks to fight with the
Nightly build for resources.

* PHP-8.1:
  .github: Bust the nightly CI cache on Sunday instead of Monday (#20242)

* PHP-8.2:
  .github: Bust the nightly CI cache on Sunday instead of Monday (#20242)

* PHP-8.3:
  .github: Bust the nightly CI cache on Sunday instead of Monday (#20242)

* PHP-8.4:
  .github: Bust the nightly CI cache on Sunday instead of Monday (#20242)

* PHP-8.5:
  .github: Bust the nightly CI cache on Sunday instead of Monday (#20242)