lsp: tracking issue for code actions features

There are a couple of LSP features that I found harder than I expected to implement (and I am not a heavy user of these features), but if anyone happens to read this and enjoy the challenge, they are:

1. Quickfix: Fix only the selected lint. Here's a template for how one might edit lsp.py (the TODO is the hard part):
```python
def diagnostic_generator(
self, uri: str, autofix: bool = False
) -> Optional[Generator[Result, bool, Optional[FileContent]]]:
# ... existing code ...
for result in generator:
violation = result.violation
if not violation:
continue
diagnostic = Diagnostic(
# ... existing fields ...
code=violation.rule_name,
source="fixit",
data={
"fix": # TODO: convert violation.replacement, a CSTNode, to a replacement string
},
)
diagnostics.append(diagnostic)
# ... existing code ...

def code_action(self, params: CodeActionParams) -> List[CodeAction]:
uri = params.text_document.uri
diagnostics = params.context.diagnostics
actions = []

for diagnostic in diagnostics:
if "fix" in diagnostic.data:
fix = diagnostic.data["fix"]

action = CodeAction(
title=f"Fix: {diagnostic.code}",
kind=CodeActionKind.QuickFix,
edit=WorkspaceEdit(
changes={
uri: [
TextEdit(
range=diagnostic.range,
new_text=fix,
)
]
}
),
)
actions.append(action)

return actions
```
2. Insert ignore comment: The hard part here is figuring out where to insert the comment.

For context, the code actions menu is the menu that comes from a light bulb next to the yellow squiggly under a lint issue. A good example of an extension that has this is the ESLint extension (built-in to VSCode I believe). Ruff also has these features, although I'm sure their model is very different so I'm not sure how easy it is to take inspiration.