[V3] Update code standards (black code format pass) (#1650)

* ran black: code formatter against `redbot/` with `-l 99`

* badge

redbot/cogs/downloader/converters.py

@@ -5,6 +5,7 @@ from .installable import Installable
 
 
 class InstalledCog(commands.Converter):
+
     async def convert(self, ctx: commands.Context, arg: str) -> Installable:
         downloader = ctx.bot.get_cog("Downloader")
         if downloader is None:
@@ -12,8 +13,6 @@ class InstalledCog(commands.Converter):
 
         cog = discord.utils.get(await downloader.installed_cogs(), name=arg)
         if cog is None:
-            raise commands.BadArgument(
-                "That cog is not installed"
-            )
+            raise commands.BadArgument("That cog is not installed")
 
         return cog