Remove extra file check in documentHighlights (#177879)

Fixes #177823

For document hightlights, it seems TS returns windows paths that use forward slashes. This seems wrong, but we also likely don't need the extra check for the file on our side either since we already pass in `filesToSearch`

extensions/typescript-language-features/src/languageFeatures/documentHighlight.ts

@@ -33,10 +33,7 @@ class TypeScriptDocumentHighlightProvider implements vscode.DocumentHighlightPro
 			return [];
 		}
 
-		return response.body
-			.filter(highlight => highlight.file === file)
-			.map(convertDocumentHighlight)
-			.flat();
+		return response.body.flatMap(convertDocumentHighlight);
 	}
 }