Make providers available to Quick Action prompts

[StructByLightning]

Validations

• [X] I believe this is a way to improve. I'll try to join the Continue Discord for questions
• [X] I'm not able to find an open issue that requests the same enhancement

Problem

One thing I use quick actions for is drafting JSDoc comments for functions. I've found that using the @codebase provider dramatically improves documentation quality, but I can't use @codebase in the quick action prompt. (I've tried @codebase and {{{ codebase }}} and neither worked.)

Solution

Quick action prompts defined in config.json could use the same syntax to invoke a provider as prompt files do.