The MISC2-MISC6 button strings are recognized by SDL3 but were not
mapped in Godot's JoyButton enum, causing 'Unrecognized output string'
warnings for controllers that use these buttons.
This adds:
- JoyButton::MISC2-MISC6 enum values (21-25)
- 'misc2'-'misc6' string mappings in _joy_buttons array
- GDScript bindings for JOY_BUTTON_MISC2 through JOY_BUTTON_MISC6
- Documentation entries in @GlobalScope.xml
- Updates JoyButton::SDL_MAX from 21 to 26
CHIKI Badreddine
bea703ae12