Add WGSL mode for syntax highlighting

Using a fork to fix some regex errors.  I am not sure why their
version of regex is different from mine, but I was able to get it
working.  Made a fork on github.

.gitmodules

@@ -0,0 +1,4 @@
+[submodule "emacs/github-packages/wgsl-mode"]
+	path = emacs/github-packages/wgsl-mode
+	url = https://github.com/glfmn/wgsl-mode
+	branch = fix-regex

emacs/github-packages/wgsl-mode

@@ -0,0 +1 @@
+Subproject commit cf2779ec15cb6315f2d887a7287afc7da5d734b9

emacs/init.el

@@ -236,4 +236,7 @@
   :diminish cargo-minor-mode
   :hook (rust-mode . cargo-minor-mode))
 
+(use-package wgsl-mode
+  :load-path "~/.emacs.d/github-packages/wgsl-mode"
+  :mode "\\.wgsl\\'")
 ;;; init.el ends here