fix: return annotations (#7118)

* chore: remove suppress annotations

* chore: remove fileoverview annotation

* chore: remove other unused annotations

* chore: change return to returns

* chore: enable tag linting

blocks/variables.ts

@@ -4,11 +4,6 @@
  * SPDX-License-Identifier: Apache-2.0
  */
 
-/**
- * @fileoverview Variable blocks for Blockly.
- * @suppress {checkTypes}
- */
-
 import * as goog from '../closure/goog/goog.js';
 goog.declareModuleId('Blockly.libraryBlocks.variables');