Implement AppCommand mentions

discord/app_commands/models.py

@@ -217,6 +217,11 @@ class AppCommand(Hashable):
     def __repr__(self) -> str:
         return f'<{self.__class__.__name__} id={self.id!r} name={self.name!r} type={self.type!r}>'
 
+    @property
+    def mention(self) -> str:
+        """:class:`str`: Returns a string that allows you to mention the given AppCommand."""
+        return f'</{self.name}:{self.id}>'
+
     @property
     def guild(self) -> Optional[Guild]:
         """Optional[:class:`~discord.Guild`]: Returns the guild this command is registered to
@@ -845,6 +850,32 @@ class AppCommandGroup:
     def __repr__(self) -> str:
         return f'<{self.__class__.__name__} name={self.name!r} type={self.type!r}>'
 
+    @property
+    def qualified_name(self) -> str:
+        """:class:`str`: Returns the fully qualified command name.
+
+        The qualified name includes the parent name as well. For example,
+        in a command like ``/foo bar`` the qualified name is ``foo bar``.
+        """
+        # A B C
+        #     ^ self
+        #   ^ parent
+        # ^ grandparent
+        names = [self.name, self.parent.name]
+        if isinstance(self.parent, AppCommandGroup):
+            names.append(self.parent.parent.name)
+
+        return ' '.join(reversed(names))
+
+    @property
+    def mention(self) -> str:
+        """:class:`str`: Returns a string that allows you to mention the given AppCommandGroup."""
+        if isinstance(self.parent, AppCommand):
+            base_command = self.parent
+        else:
+            base_command = self.parent.parent
+        return f'</{self.qualified_name}:{base_command.id}>'  # type: ignore
+
     def _from_data(self, data: ApplicationCommandOption) -> None:
         self.type: AppCommandOptionType = try_enum(AppCommandOptionType, data['type'])
         self.name: str = data['name']