nixos/test-driver: fix formatting

This caused the test driver to fail to build.

Fixes: 406de94b41 ("nixos/test-driver: add `timeout` option for `wait_for_console_text`")

nixos/lib/test-driver/test_driver/machine.py

@@ -867,6 +867,7 @@ class Machine:
         # Buffer the console output, this is needed
         # to match multiline regexes.
         console = io.StringIO()
+
         def console_matches() -> bool:
             nonlocal console
             try:
@@ -877,7 +878,7 @@ class Machine:
                 pass
             console.seek(0)
             matches = re.search(regex, console.read())
-            return (matches is not None)
+            return matches is not None
 
         with self.nested(f"waiting for {regex} to appear on console"):
             if timeout is not None: