Suggestion: Make `@param;@return` available as code action

还没有人认领这个 Issue。

One really nice feature of the lua-lsp is that by typing `---` above a function, we get the `@param;@return` suggestions which auto-inserts function annotation.

Would it be possible to make this feature available via code action as well? Right now, it takes a bit of repetitive work to get the annotations inserted. When at the function head: `up`, `-`. `-`, `-`, `enter`. By using a code action, this could be reduced to one hotkey (and depending on your editor, maybe one extra `enter`).

Another benefit would be that making this available as code action would increase the discoverability of this feature. For a while, I didn't know that this very useful feature even existed. By being a code action, it would be far easier to discover for new users.

首先跟踪由 `---` 触发、用于插入 `@param` 和 `@return` 注解的现有建议，然后检查 language server 在哪里提供代码操作。完成的标准是：可以通过代码操作执行相同的注解插入，并且在函数头部仍然可以发现该功能。

由索引模型根据 Issue 内容生成。