Add a cooldown example (Pycord-Development#677)

examples/cooldown.py

@@ -0,0 +1,36 @@
+import discord
+from discord.ext import commands
+
+
+bot = commands.Bot()
+
+
+# an application command with cooldown
+@bot.slash_command()
+@commands.cooldown(1, 5, commands.BucketType.user)  # the command can only be used once in 5 seconds
+async def slash(ctx):
+    await ctx.respond("You can't use this command again in 5 seconds.")
+
+
+# error handler
+@bot.event
+async def on_application_command_error(ctx, error):
+    if isinstance(error, commands.CommandOnCooldown):
+        await ctx.respond("This command is currently on cooldown.")
+    else:
+        raise error  # raise other errors so they aren't ignored
+
+
+# a prefixed command with cooldown
+@bot.command()
+@commands.cooldown(1, 5, commands.BucketType.user)
+async def prefixed(ctx):
+    await ctx.send("You can't use this command again in 5 seconds.")
+
+
+@bot.event
+async def on_command_error(ctx, error):
+    if isinstance(error, commands.CommandOnCooldown):
+        await ctx.send("This command is currently on cooldown.")
+    else:
+        raise error