ASDFMovie Cave Sounds

Added proper multi-version support using overlays. 1.21.4 and above use a separate sounds.json due to the subtitle key for cave sounds being changed to "subtitles.ambient.sound" for whatever reason. 1.21.3 and below use the original sounds.json with "subtitles.ambient.cave".

As a result of the above change, use of an en_us.json lang file has returned.

Removed the abbreviation of "MC" from the flavor text, as I assume you're at least smart enough to understand what the following numbers mean. Changed it to say "1.7.2 - 26.1 pre2".

Bumped supported format up to 84.0 to match with 26.1 pre2.