test(language_server): fix test for ServerFormatter in windows (#14210)

The language server formatter tests were failing on Windows due to line ending differences between platforms. This caused snapshot test mismatches, leading to the test being disabled on Windows.

The fix ensures that during tests on Windows, source files are normalized to use LF line endings, making the formatting results consistent with Linux snapshots and allowing the test to run successfully on all platforms.

`FormatOptions::line_ending` default value is LF ending, changing it only for windows will still result into snapshot changes.

Author: Sysix

crates/oxc_language_server/src/formatter/server_formatter.rs

@@ -21,7 +21,13 @@ impl ServerFormatter {
         let source_text = if let Some(content) = content {
             content
         } else {
-            std::fs::read_to_string(&path).ok()?
+            #[cfg(not(all(test, windows)))]
+            let source_text = std::fs::read_to_string(&path).ok()?;
+            #[cfg(all(test, windows))]
+            #[expect(clippy::disallowed_methods)] // no `cow_replace` in tests are fine
+            // On Windows, convert CRLF to LF for consistent formatting results
+            let source_text = std::fs::read_to_string(&path).ok()?.replace("\r\n", "\n");
+            source_text
         };
 
         let allocator = Allocator::new();
@@ -191,7 +197,6 @@ mod tests {
     }
 
     #[test]
-    #[cfg(not(windows))] // FIXME: snapshot differs on Windows. Possible newline issue?
     fn test_formatter() {
         Tester::new("fixtures/formatter/basic", Some(FormatOptions { experimental: true }))
             .format_and_snapshot_single_file("basic.ts");