unified: Move Comments.ql into AstExtra.qll

Also move into 'internal' and expose through a Public module

unified/ql/lib/codeql/unified/Comments.qll

@@ -1,18 +0,0 @@
-/** Provides classes for working with comments. */
-
-private import unified
-
-/**
- * A comment appearing in the source code.
- */
-class Comment extends TriviaToken {
-  // At the moment, comments are the only type trivia token we extract
-  /**
-   * Gets the text inside this comment, not counting the delimeters.
-   */
-  string getCommentText() {
-    result = this.getValue().regexpCapture("//(.*)", 1)
-    or
-    result = this.getValue().regexpCapture("(?s)/\\*(.*)\\*/", 1)
-  }
-}

unified/ql/lib/codeql/unified/internal/AstExtra.qll

@@ -0,0 +1,22 @@
+/**
+ * Provides additional AST-like classes outside the generated tree-sitter classes.
+ */
+
+private import unified
+
+module Public {
+  /**
+   * A comment appearing in the source code.
+   */
+  class Comment extends TriviaToken {
+    // At the moment, comments are the only type trivia token we extract
+    /**
+     * Gets the text inside this comment, not counting the delimeters.
+     */
+    string getCommentText() {
+      result = this.getValue().regexpCapture("//(.*)", 1)
+      or
+      result = this.getValue().regexpCapture("(?s)/\\*(.*)\\*/", 1)
+    }
+  }
+}

unified/ql/lib/unified.qll

@@ -5,4 +5,4 @@
 import codeql.Locations
 import codeql.files.FileSystem
 import codeql.unified.Ast::Unified
-import codeql.unified.Comments
+import codeql.unified.internal.AstExtra::Public