!fixup e62ebcb test(scp): clarify the creation of "pipe|"

Author: akinomyoga

test/t/test_scp.py

@@ -191,6 +191,8 @@ def test_xfunc_remote_files(self, bash):
 
     @pytest.fixture
     def tmpdir_mkfifo(self, request, bash):
+        # We prepare two files: 1) a named pipe and 2) a regular file ending
+        # with the same name but an extra special character "|".
         tmpdir, _, _ = prepare_fixture_dir(
             request,
             files=["local_path_2-pipe|"],