[Mod] Add [p]slowmode (#2734)

Makes use of new timedelta converter

redbot/cogs/mod/mod.py

@@ -12,6 +12,7 @@ from .kickban import KickBanMixin
 from .movetocore import MoveToCore
 from .mutes import MuteMixin
 from .names import ModInfo
+from .slowmode import Slowmode
 from .settings import ModSettings
 
 _ = T_ = Translator("Mod", __file__)
@@ -36,6 +37,7 @@ class Mod(
     MoveToCore,
     MuteMixin,
     ModInfo,
+    Slowmode,
     commands.Cog,
     metaclass=CompositeMetaClass,
 ):