11699: feat: assist to remove unneeded `async`s r=Ethiraric a=Ethiraric
This should fix#11392
This PR adds a quickfix on functions marked with `async` that suggests, if and only if no `await` expression in find in the body of the function (it relies on `SyntaxNode::descendants()` to recursively traverse blocks), to remove the `async` keyword.
The lint is made so that it triggers only if the cursor is not in the body of the function, so that it does not pollute the quickfix list.
It does not trigger a diagnostic. I don't know if this repository is the place to implement those (`clippy`?). If it is, I would very much like pointers on where to start looking.
If there are test cases I haven't thought about, please do suggest.
Co-authored-by: Ethiraric <ethiraric@gmail.com>
63d2df1e36