Mark the emulation as a best effort, not a specification

Author: serhiy-storchaka

Lib/ntpath.py

@@ -517,7 +517,9 @@ def normpath(path):
 
 except ImportError: # not running on Windows - mock up something sensible
     def _strip_dots_and_spaces(path):
-        # As the Windows path normalization does.
+        # Imitate the trailing dot and space stripping performed by the
+        # Windows path normalization.  This is a best effort, not a
+        # specification.
         if isinstance(path, bytes):
             sep = b'\\'
             dot = b'.'

Lib/test/test_ntpath.py

@@ -1213,6 +1213,7 @@ def test_expanduser(self):
     def test_abspath_dots_and_spaces(self):
         # gh-85681: trailing dots and spaces are stripped from the last
         # component, and a single trailing dot from other components.
+        # This is the observed Windows behavior, not a specification.
         tester('ntpath.abspath("C:/spam. . .")', "C:\\spam")
         tester('ntpath.abspath("C:/spam.")', "C:\\spam")
         tester('ntpath.abspath("C:/spam ")', "C:\\spam")