[Core] Guild scoped I18n (#3896)

* Guild I18n

Never again!

* Finish off guild scoped i18n

* Black formatting

* Added guild only flags.

* Fix missing import.

* Added listing of guild i18n settings

* Added API support

* Added API support... properly!

* Added API support... for realsies!

* Auto-translate create_cases instances

You're welcome cog creators! Jack talked me into this!

* Fix get_regional_format to actually return properly

* Cleanup `set showsettings`

* Style pass

* Update redbot/core/core_commands.py

Co-authored-by: jack1142 <6032823+jack1142@users.noreply.github.com>

* Update redbot/core/events.py

Co-authored-by: jack1142 <6032823+jack1142@users.noreply.github.com>

* Update redbot/core/core_commands.py

Co-authored-by: jack1142 <6032823+jack1142@users.noreply.github.com>

* Fix missing import

* Improve caching

* Removal of unneeded function

* Fix some naming

* IDFK anymore...

* Reformat

* Update redbot/core/settings_caches.py

Co-authored-by: jack1142 <6032823+jack1142@users.noreply.github.com>

* Update redbot/core/settings_caches.py

Co-authored-by: jack1142 <6032823+jack1142@users.noreply.github.com>

* Update redbot/core/settings_caches.py

Co-authored-by: jack1142 <6032823+jack1142@users.noreply.github.com>

* Remove line number

* Fix global sets

* Set contextual locale manually where needed

* Reports cog is wonderful...

* Update redbot/core/core_commands.py

Co-authored-by: Draper <27962761+Drapersniper@users.noreply.github.com>

* Set contextual locale manually where needed in Mutes cog

* s

Co-authored-by: jack1142 <6032823+jack1142@users.noreply.github.com>
Co-authored-by: Draper <27962761+Drapersniper@users.noreply.github.com>

redbot/cogs/streams/streams.py

@@ -1,7 +1,7 @@
 import discord
 from redbot.core.bot import Red
 from redbot.core import checks, commands, Config
-from redbot.core.i18n import cog_i18n, Translator
+from redbot.core.i18n import cog_i18n, Translator, set_contextual_locales_from_guild
 from redbot.core.utils._internal_utils import send_to_owners_with_prefix_replaced
 from redbot.core.utils.chat_formatting import escape, pagify
 
@@ -714,6 +714,9 @@ class Streams(commands.Cog):
                         ignore_reruns = await self.config.guild(channel.guild).ignore_reruns()
                         if ignore_reruns and is_rerun:
                             continue
+
+                        await set_contextual_locales_from_guild(self.bot, channel.guild)
+
                         mention_str, edited_roles = await self._get_mention_str(
                             channel.guild, channel
                         )