Add rule to find hardcoded docs urls (#42212)

src/content-linter/style/github-docs.js

@@ -34,6 +34,11 @@ export const githubDocsConfig = {
     severity: 'error',
     'partial-markdown-files': true,
   },
+  'no-github-docs-domains': {
+    // GHD020
+    severity: 'error',
+    'partial-markdown-files': true,
+  },
   'search-replace': {
     severity: 'error',
     'severity-local-env': 'warning',
@@ -45,6 +50,34 @@ export const githubDocsConfig = {
         search: 'TODOCS',
         searchScope: 'all',
       },
+      {
+        name: 'docs-domain',
+        message: 'Catch occurrences of docs.gitub.com domain.',
+        search: 'docs.gitub.com',
+        searchScope: 'all',
+      },
+      {
+        name: 'help-domain',
+        message: 'Catch occurrences of help.github.com domain.',
+        search: 'help.github.com',
+        searchScope: 'all',
+      },
+      {
+        name: 'preview-domain',
+        message: 'Catch occurrences of preview.ghdocs.com domain.',
+        search: 'preview.ghdocs.com',
+        searchScope: 'all',
+      },
+      {
+        name: 'developer-domain',
+        message: 'Catch occurrences of developer.github.com domain.',
+        // Do not match developer.github.com/changes or
+        // developer.github.com/enterprise/[0-9] or
+        // developer.github.com/enterprise/{{something}} (e.g. liquid).
+        // There are occurences that will likely always remain in the content.
+        searchPattern: '/developer.github.com(?!/(changes|enterprise/([0-9]|{))).*/g',
+        searchScope: 'all',
+      },
     ],
   },
 }