Combine lint and syntax error handling (#18471)

## Summary

This is a spin-off from
https://github.com/astral-sh/ruff/pull/18447#discussion_r2125844669 to
avoid using `Message::noqa_code` to differentiate between lints and
syntax errors. I went through all of the calls on `main` and on the
branch from #18447, and the instance in `ruff_server` noted in the
linked comment was actually the primary place where this was being done.
Other calls to `noqa_code` are typically some variation of
`message.noqa_code().map_or(String::new, format!(...))`, with the major
exception of the gitlab output format:


a120610b5b/crates/ruff_linter/src/message/gitlab.rs (L93-L105)

which obviously assumes that `None` means syntax error. A simple fix
here would be to use `message.name()` for `check_name` instead of the
noqa code, but I'm not sure how breaking that would be. This could just
be:

```rust
 let description = message.body();
 let description = description.strip_prefix("SyntaxError: ").unwrap_or(description).to_string();
 let check_name = message.name();
```

In that case. This sounds reasonable based on the [Code Quality report
format](https://docs.gitlab.com/ci/testing/code_quality/#code-quality-report-format)
docs:

> | Name | Type | Description|
> |-----|-----|----|
> |`check_name` | String | A unique name representing the check, or
rule, associated with this violation. |

## Test Plan

Existing tests

crates/ruff_wasm/src/lib.rs

@@ -207,36 +207,23 @@ impl Workspace {
 
         let messages: Vec<ExpandedMessage> = messages
             .into_iter()
-            .map(|msg| {
-                let message = msg.body().to_string();
-                let range = msg.range();
-                match msg.to_noqa_code() {
-                    Some(code) => ExpandedMessage {
-                        code: Some(code.to_string()),
-                        message,
-                        start_location: source_code.line_column(range.start()).into(),
-                        end_location: source_code.line_column(range.end()).into(),
-                        fix: msg.fix().map(|fix| ExpandedFix {
-                            message: msg.suggestion().map(ToString::to_string),
-                            edits: fix
-                                .edits()
-                                .iter()
-                                .map(|edit| ExpandedEdit {
-                                    location: source_code.line_column(edit.start()).into(),
-                                    end_location: source_code.line_column(edit.end()).into(),
-                                    content: edit.content().map(ToString::to_string),
-                                })
-                                .collect(),
-                        }),
-                    },
-                    None => ExpandedMessage {
-                        code: None,
-                        message,
-                        start_location: source_code.line_column(range.start()).into(),
-                        end_location: source_code.line_column(range.end()).into(),
-                        fix: None,
-                    },
-                }
+            .map(|msg| ExpandedMessage {
+                code: msg.to_noqa_code().map(|code| code.to_string()),
+                message: msg.body().to_string(),
+                start_location: source_code.line_column(msg.start()).into(),
+                end_location: source_code.line_column(msg.end()).into(),
+                fix: msg.fix().map(|fix| ExpandedFix {
+                    message: msg.suggestion().map(ToString::to_string),
+                    edits: fix
+                        .edits()
+                        .iter()
+                        .map(|edit| ExpandedEdit {
+                            location: source_code.line_column(edit.start()).into(),
+                            end_location: source_code.line_column(edit.end()).into(),
+                            content: edit.content().map(ToString::to_string),
+                        })
+                        .collect(),
+                }),
             })
             .collect();