fix: Do not scan all Go files for tailwind classes

Reduces some noise in the index.css file and adds a comment why it was done in the first place.

tailwind.config.js

@@ -32,11 +32,14 @@ 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}',
+    // explicitly list Go files that contain tailwind classes
+    'models/avatars/avatar.go',
+    'modules/markup/file_preview.go',
+    'modules/markup/sanitizer.go',
+    'services/auth/source/oauth2/*.go',
+    'routers/web/repo/{view,blame,issue_content_history}.go',
   ].filter(Boolean),
   blocklist: [
     // classes that don't work without CSS variables from "@tailwind base" which we don't use