fix typo in warning (#20620)

* Add space after period to warning in _tzpath.py

Currently:
InvalidTZPathWarning: Invalid paths specified in PYTHONTZPATH environment variable.Paths should be absolute but found the following relative paths: ...

* Update _tzpath.py
diff --git a/Lib/zoneinfo/_tzpath.py b/Lib/zoneinfo/_tzpath.py
index 9513611..672560b 100644
--- a/Lib/zoneinfo/_tzpath.py
+++ b/Lib/zoneinfo/_tzpath.py
@@ -42,7 +42,7 @@ def _parse_python_tzpath(env_var):
         msg = _get_invalid_paths_message(raw_tzpath)
 
         warnings.warn(
-            "Invalid paths specified in PYTHONTZPATH environment variable."
+            "Invalid paths specified in PYTHONTZPATH environment variable. "
             + msg,
             InvalidTZPathWarning,
         )