Add redbot.core.app_commands namespace (#6006)

tests/core/test_app_commands.py

@@ -0,0 +1,23 @@
+import inspect
+
+import pytest
+from discord import app_commands as dpy_app_commands
+
+from redbot.core import app_commands
+
+
+def test_dpy_app_commands_reexports():
+    dpy_attrs = set()
+    for attr_name, attr_value in dpy_app_commands.__dict__.items():
+        if attr_name.startswith("_") or inspect.ismodule(attr_value):
+            continue
+
+        dpy_attrs.add(attr_name)
+
+    missing_attrs = dpy_attrs - set(app_commands.__dict__.keys())
+
+    if missing_attrs:
+        pytest.fail(
+            "redbot.core.app_commands is missing these names from discord.app_commands: "
+            + ", ".join(missing_attrs)
+        )