Lint errors should be removed on file write

[mattysweeps]

I'm not sure if this bug belongs in the extension or the language server itself. Since I use the extension I'm posting it here first.

Describe the bug
Some linters take a long time to run. This often leads to stale lint errors after I save a file.

Expected behavior
It would be nice if all lint errors from the diagnostic language server were cleared when the file is written. If there's an autocmd for this, that would work too.

[iamcco]

It is not support yet.