Rework slash command enum values pt.2

- Fix jsconfig module resolution for imports in frontend scripts
- Add file with common slash command enum values

public/scripts/slash-commands/SlashCommandClosure.js

@@ -93,7 +93,7 @@ export class SlashCommandClosure {
 
     /**
      *
-     * @returns Promise<SlashCommandClosureResult>
+     * @returns {Promise<SlashCommandClosureResult>}
      */
     async execute() {
         const closure = this.getCopy();