Add server config to filter out syntax error diagnostics (#12059)
## Summary
Follow-up from #11901
This PR adds a new server setting to show / hide syntax errors.
## Test Plan
### VS Code
Using https://github.com/astral-sh/ruff-vscode/pull/504 with the
following config:
```json
{
"ruff.nativeServer": true,
"ruff.path": ["/Users/dhruv/work/astral/ruff/target/debug/ruff"],
"ruff.showSyntaxErrors": true
}
```
First, set `ruff.showSyntaxErrors` to `true`:
<img width="1177" alt="Screenshot 2024-06-27 at 08 34 58"
src="https://github.com/astral-sh/ruff/assets/67177269/5d77547a-a908-4a00-8714-7c00784e8679">
And then set it to `false`:
<img width="1185" alt="Screenshot 2024-06-27 at 08 35 19"
src="https://github.com/astral-sh/ruff/assets/67177269/9720f089-f10c-420b-a2c1-2bbb2245be35">
### Neovim
Using the following Ruff server config:
```lua
require('lspconfig').ruff.setup {
init_options = {
settings = {
showSyntaxErrors = false,
},
},
}
```
First, set `showSyntaxErrors` to `true`:
<img width="1279" alt="Screenshot 2024-06-27 at 08 28 03"
src="https://github.com/astral-sh/ruff/assets/67177269/e694e231-91ba-47f8-8e8a-ad2e82b85a45">
And then set it to `false`:
<img width="1284" alt="Screenshot 2024-06-27 at 08 28 20"
src="https://github.com/astral-sh/ruff/assets/67177269/25b86a57-02b1-44f7-9f65-cf5fdde93b0c">
