[commands] Add custom exception classes for built-in checks

Added:
* MissingRole
* BotMissingRole
* MissingAnyRole
* BotMissingAnyRole

docs/ext/commands/api.rst

@@ -255,6 +255,9 @@ Exceptions
 .. autoexception:: discord.ext.commands.BadUnionArgument
     :members:
 
+.. autoexception:: discord.ext.commands.PrivateMessageOnly
+    :members:
+
 .. autoexception:: discord.ext.commands.NoPrivateMessage
     :members:
 
@@ -288,6 +291,21 @@ Exceptions
 .. autoexception:: discord.ext.commands.BotMissingPermissions
     :members:
 
+.. autoexception:: discord.ext.commands.MissingRole
+    :members:
+
+.. autoexception:: discord.ext.commands.BotMissingRole
+    :members:
+
+.. autoexception:: discord.ext.commands.MissingAnyRole
+    :members:
+
+.. autoexception:: discord.ext.commands.BotMissingAnyRole
+    :members:
+
+.. autoexception:: discord.ext.commands.NSFWChannelRequired
+    :members:
+
 .. autoexception:: discord.ext.commands.ExtensionError
     :members:
 
@@ -326,10 +344,16 @@ Exception Hierarchy
                     - :exc:`~.commands.ExpectedClosingQuoteError`
             - :exc:`~.commands.CommandNotFound`
             - :exc:`~.commands.CheckFailure`
+                - :exc:`~.commands.PrivateMessageOnly`
                 - :exc:`~.commands.NoPrivateMessage`
                 - :exc:`~.commands.NotOwner`
                 - :exc:`~.commands.MissingPermissions`
                 - :exc:`~.commands.BotMissingPermissions`
+                - :exc:`~.commands.MissingRole`
+                - :exc:`~.commands.BotMissingRole`
+                - :exc:`~.commands.MissingAnyRole`
+                - :exc:`~.commands.BotMissingAnyRole`
+                - :exc:`~.commands.NSFWChannelRequired`
             - :exc:`~.commands.DisabledCommand`
             - :exc:`~.commands.CommandInvokeError`
             - :exc:`~.commands.CommandOnCooldown`