Added events docs

Author: eunwoo1104

docs/discord_slash.rst

@@ -5,7 +5,7 @@ Submodules
 ----------
 
 .. toctree::
-   :maxdepth: 2
+   :maxdepth: 4
 
    discord_slash.client
    discord_slash.error

docs/events.rst

@@ -0,0 +1,22 @@
+discord-py-slash-command Events
+================================
+This page is about events of this extension.
+These events can be registered to discord.py's listener or
+``event`` decorator.
+
+.. function:: on_slash_command(ctx)
+
+    Called when slash command is triggered.
+
+    :param ctx: SlashContext of the triggered command.
+    :type ctx: :class:`.model.SlashContext`
+
+.. function:: on_slash_command_error(ctx, ex)
+
+    Called when slash command had an exception while the command was invoked.
+
+    :param ctx: SlashContext of the triggered command.
+    :type ctx: :class:`.model.SlashContext`
+    :param ex: Exception that raised.
+    :type ex: Exception
+

docs/index.rst

@@ -35,6 +35,7 @@ Example:
    :caption: Contents:
 
    discord_slash.rst
+   events.rst
    discord_slash.utils.rst