Include go files in tailwind processing (#29686)

We need to scan `.go` files for tailwind classes. Does not seem to
affect build time much luckily.

Fixes:
#29678 (comment)

Verified via `rg tw-object-contain public/assets/css/index.css`.

---------

Co-authored-by: Giteabot <teabot@gitea.io>

tailwind.config.js

@@ -31,6 +31,9 @@ export default {
     isProduction && '!./web_src/js/standalone/devtest.js',
     '!./templates/swagger/v1_json.tmpl',
     '!./templates/user/auth/oidc_wellknown.tmpl',
+    '!**/*_test.go',
+    '!./modules/{public,options,templates}/bindata.go',
+    './{build,models,modules,routers,services}/**/*.go',
     './templates/**/*.tmpl',
     './web_src/js/**/*.{js,vue}',
   ].filter(Boolean),