chat api improvements for probably after 1.20 because i took too long

[SilverAndro]

This took a while, probably lots of nitpicking to do (especially with javadoc)

Changes:

• Test mod is significantly improved
• TypedChatApiHook is no longer api
• Errors from events now try to show where the error is from
• Support for chat signing
• Support for commands
• Support for message removal (this isnt used in vanilla so, i think my impl works?)

Testing:

This PR is mostly tested locally, but because i only have 1 minecraft account and no friends, i couldn't test several sections of this PR, notably:

• Cancelling INBOUND CLIENT CHAT
• How this works with commands like /msg, especially between players not privy to the conversation
• Probably other things i dont remember