Fix typo within HelpCommand.verify_checks documentation

Author: Kellenn

discord/ext/commands/help.py

@@ -278,7 +278,7 @@ class HelpCommand:
         If ``None``, only calls :attr:`.Commands.checks` in a guild setting.
         If ``False``, never calls :attr:`.Commands.checks`. Defaults to ``True``.
 
-        ..versionchanged:: 1.7
+        .. versionchanged:: 1.7
     command_attrs: :class:`dict`
         A dictionary of options to pass in for the construction of the help command.
         This allows you to change the command behaviour without actually changing