php: 8.2 -> 8.3

PHP 8.2 will only receive security patches starting at the end of
November[1], so it makes sense to bump the default version forward.

I looked through all modules with the substring `pkgs.php`[2] and all of
the usages looked fine or were fixed in a commit before this one.

[1] https://www.php.net/supported-versions.php
[2] I didn't take `with`/`let ... in` things into account, but honestly,
    if an application doesn't work with a newer PHP, it should probably
    be pinned down instead of blindly relying on `pkgs.php`.

nixos/doc/manual/release-notes/rl-2505.section.md

@@ -4,7 +4,7 @@
 
 <!-- To avoid merge conflicts, consider adding your item at an arbitrary place in the list instead. -->
 
-- Create the first release note entry in this section!
+- The default PHP version has been updated to 8.3.
 
 <!-- To avoid merge conflicts, consider adding your item at an arbitrary place in the list instead. -->
 

pkgs/top-level/all-packages.nix

@@ -7439,7 +7439,7 @@ with pkgs;
   # PHP interpreters, packages and extensions.
   #
   # Set default PHP interpreter, extensions and packages
-  php = php82;
+  php = php83;
   phpExtensions = php.extensions;
   phpPackages = php.packages;