Make sure we normalize paths before sending them to tsserver

Fixes #84826

extensions/typescript-language-features/src/typescriptServiceClient.ts

@@ -575,11 +575,15 @@ export default class TypeScriptServiceClient extends Disposable implements IType
 			return undefined;
 		}
 
-		const result = resource.fsPath;
+		let result = resource.fsPath;
 		if (!result) {
 			return undefined;
 		}
 
+		if (resource.scheme === fileSchemes.file) {
+			result = path.normalize(result);
+		}
+
 		// Both \ and / must be escaped in regular expressions
 		return result.replace(new RegExp('\\' + this.pathSeparator, 'g'), '/');
 	}