Auto Join Party and Raid Group Chat Channel

Tl;dr = The addon has 3 features

💠 (1.) After joining into a [Party] group, automatically switch the chat channel to /p, so it will be already selected by default the next time you press [Enter] to write a chat message.
💠 (2.) After joining into a [Raid] group, automatically switch the chat channel to /raid, so it will be already selected by default the next time you press [Enter] to write a chat message.
💠 (3.) Guards against accidentally sent /whisper messages: When you [/whisper] somebody, 2 minutes after your last /w message, the default chat channel will revert back to your previous one. So if you were in [/say] or [/party] or [/raid] chat channel, then it will put that back the next time you open the chat with [Enter]. This is an extra handy feature when you often [/whisper] people from the [Trade Chat] to offer crafting the item that they search.

💠 Extra Info 💠
To completely turn off the [/whisper] handling, use this toggle (default on): /autojoin whisper
(The setting is saved account wide, so you don't need to set this for all of your characters)

The addon is very minimalistic, carefully crafted code, only takes 1kb, it only does these changes once, when you join a group, so it doesn't try to refresh itself everytime someone joins into your group, etc.
Works in Random Dungeon Queue, and Timewalking too, with the "/instance" chat channel.

💠 The Default Game Behavior That This Minimalistic Addon changes 💠
After joining into a [Party] group, the next time you press [Enter] to write a chat message, the "/say" chat channel was selected, which was giga annoying.
After joining into a [Raid] group, the next time you press [Enter] to write a chat message, the "/say" chat channel was selected, which was giga annoying.
After you send a [/whisper] to somebody, this "/whisper" channel will stay in your chat forever, until you manually change it, or log-out, which was giga annoying.

💠 Feedback 💠
I only play and test in Retail version, so i have no info about Classic compatibility.
Any bug reports are welcome in the comments section.