Further clarify how bots can interact with emoji endpoints

Clarifies that bot accounts can only interact with emoji they have
created.

discord/emoji.py

@@ -193,6 +193,8 @@ class Emoji(Hashable):
         You must have :attr:`~Permissions.manage_emojis` permission to
         do this.
 
+        Note that bot accounts can only delete custom emojis they own.
+
         Parameters
         -----------
         reason: Optional[str]
@@ -217,6 +219,8 @@ class Emoji(Hashable):
         You must have :attr:`~Permissions.manage_emojis` permission to
         do this.
 
+        Note that bot accounts can only edit custom emojis they own.
+
         Parameters
         -----------
         name: str

discord/guild.py

@@ -971,6 +971,8 @@ class Guild(Hashable):
 
         There is currently a limit of 50 local emotes per guild.
 
+        Note that bot accounts can only edit and delete emojis they have created.
+
         Parameters
         -----------
         name: str