Hotbars+ v1.3-Pre4

This is a prerelease version. It may not be entirely stable.

Additions:

• Adds an experimental new keybind for backups. It isn't set to anything by default, so you'll need to bind it yourself.

Changes:

• Additional code clean-up and documentation
• Cuts off support for versions after 1.16.5 because clients would crash in 1.17+ as a result of mappings differences.
• Replaces the backup button's icon (initially✍) with a new icon (a floppy disk).
• Toast notifications now use custom textures instead of relying on the built-in icons.