tests(test_options): Add test for g parameter deprecation warning

why: Verify that show_option() emits DeprecationWarning when deprecated g
parameter is used
what:
- Add test_show_option_g_parameter_emits_deprecation_warning test
- Ensures backward compatibility warning is properly raised

Author: tony

tests/test_options.py

@@ -1276,3 +1276,12 @@ def test_convert_values_preserves_sparse_keys() -> None:
     assert result[0] is True
     assert result[5] is False
     assert result[99] == 100
+
+
+def test_show_option_g_parameter_emits_deprecation_warning(
+    session: "Session",
+) -> None:
+    """Test show_option() emits DeprecationWarning when deprecated g parameter is used."""
+    server = session.server
+    with pytest.warns(DeprecationWarning, match=r"g argument is deprecated"):
+        server.show_option("buffer-limit", g=True)