Implement a least breaking approach to slash commands (#39)

* Most slash command support completed, needs some debugging (and reindent)

* Implement a ctx.send helper for slash commands

* Add group command support

* Add Option converter, fix default optional, fix help command

* Add client.setup and move readying commands to that

* Implement _FakeSlashMessage.from_interaction

* Rename normmal_command to message_command

* Add docs for added params

* Add slash_command_guilds to bot and decos

* Fix merge conflict

* Remove name from commands.Option, wasn't used

* Move slash command processing to BotBase.process_slash_commands

* Create slash_only.py

Basic example for slash commands

* Create slash_and_message.py

Basic example for mixed commands

* Fix slash_command and normal_command bools

* Add some basic error handling for registration

* Fixed converter upload errors

* Fix some logic and make an actual example

* Thanks Safety Jim

* docstrings, *args, and error changes

* Add proper literal support

* Add basic documentation on slash commands

* Fix non-slash command interactions

* Fix ctx.reply in slash command context

* Fix typing on Context.reply

* Fix multiple optional argument sorting

* Update ctx.message docs to mention error instead of warning

* Move slash command creation to BotBase

* Fix code style issues with Black

* Rearrange some stuff and add flag support

* Change some errors and fix interaction.channel fixing

* Fix slash command quoting for *args

Co-authored-by: iDutchy <42503862+iDutchy@users.noreply.github.com>
Co-authored-by: Lint Action <lint-action@samuelmeuli.com>

examples/slash_commands.py

@@ -0,0 +1,41 @@
+import discord
+from discord.ext import commands
+
+# Set slash commands=True when constructing your bot to enable all slash commands
+# if your bot is only for a couple of servers, you can use the parameter
+# `slash_command_guilds=[list, of, guild, ids]` to specify this,
+# then the commands will be much faster to upload.
+bot = commands.Bot("!", intents=discord.Intents(guilds=True, messages=True), slash_commands=True)
+
+
+@bot.event
+async def on_ready():
+    print(f"Logged in as {bot.user} (ID: {bot.user.id})")
+    print("------")
+
+
+@bot.command()
+# You can use commands.Option to define descriptions for your options, and converters will still work fine.
+async def ping(
+    ctx: commands.Context, emoji: bool = commands.Option(description="whether to use an emoji when responding")
+):
+    # This command can be used with slash commands or message commands
+    if emoji:
+        await ctx.send("\U0001f3d3")
+    else:
+        await ctx.send("Pong!")
+
+
+@bot.command(message_command=False)
+async def only_slash(ctx: commands.Context):
+    # This command can only be used with slash commands
+    await ctx.send("Hello from slash commands!")
+
+
+@bot.command(slash_command=False)
+async def only_message(ctx: commands.Context):
+    # This command can only be used with a message
+    await ctx.send("Hello from message commands!")
+
+
+bot.run("token")