Update mypy/test/data.py: .strip the message

Author: wyattscarpenter

mypy/test/data.py

@@ -545,7 +545,7 @@ def expand_errors(input: list[str], output: list[str], fnam: str) -> None:
                 elif m.group(1) == "W":
                     severity = "warning"
                 col = m.group("col")
-                message = m.group("message")
+                message = m.group("message").strip()
                 message = message.replace(r"\#", "#")  # adds back escaped # character
                 if col is None:
                     output.append(f"{fnam}:{i + 1}: {severity}: {message}")