fix(:lang): missing grammar recipes

I removed the grammar recipes in 3b58741 to avoid redundancy with the
upstream recipes, but didn't realize that those upstream recipes weren't
added until Emacs 31, so users on 30 and older would get errors when
trying to install any missing grammars.

This also establishes a hard dependency between :lang (php +tree-sitter)
and :lang ({javascript,web} +tree-sitter).

Amend: 3b58741522

modules/lang/rust/config.el

@@ -33,12 +33,16 @@
     (require 'rustic-mode nil t)))
 
 
-(use-package! rust-ts-mode
+(use-package! rust-ts-mode  ; 29.1+ only
   :when (modulep! +tree-sitter)
-  :when (fboundp 'rust-ts-mode) ; 29.1+ only
   :defer t
   :init
-  (set-tree-sitter! 'rust-mode 'rust-ts-mode 'rust)
+  (set-tree-sitter! 'rust-mode 'rust-ts-mode
+    `((rust :url "https://github.com/tree-sitter/tree-sitter-rust"
+            :commit ,(if (and (treesit-available-p)
+                              (< (treesit-library-abi-version) 15))
+                         "1f63b33efee17e833e0ea29266dd3d713e27e321"
+                       "18b0515fca567f5a10aee9978c6d2640e878671a"))))
 
   (add-to-list 'major-mode-remap-defaults '(rust-mode . rust-ts-mode) t))