Added an example for slash commands in cogs.

Author: Sengolda

examples/app_commands/slash_cog.py

@@ -0,0 +1,13 @@
+from discord.ext import commands
+from discord.commands import slash_command
+
+class Example(commands.Cog):
+    def __init__(self, bot):
+        self.bot = bot
+ 
+    @slash_command()
+    async def example(self, ctx):
+        await ctx.respond("Hi, this is a slash command from a cog!")
+
+def setup(bot):
+    bot.add_cog(Example(bot))