Add alias --config-file to -c (#11036)

Fixes #11031

Signed-off-by: Chris Mahoney <chrismahoey@hotmail.com>
Co-authored-by: Chris Mahoney <chrismahoey@hotmail.com>

src/_pytest/main.py

@@ -122,11 +122,12 @@ def pytest_addoption(parser: Parser) -> None:
     )
     group._addoption(
         "-c",
-        metavar="file",
+        "--config-file",
+        metavar="FILE",
         type=str,
         dest="inifilename",
-        help="Load configuration from `file` instead of trying to locate one of the "
-        "implicit configuration files",
+        help="Load configuration from `FILE` instead of trying to locate one of the "
+        "implicit configuration files.",
     )
     group._addoption(
         "--continue-on-collection-errors",