Document our support

[jamierocks]

We should document what we can remap, and our current limitations.

[phase]

We do support:

• @Mixin
• @Inject
• @Overwrite
• @Shadow
• @Accessor, @Invoker
• @At
• @Redirect
• @ModifyConstant, @ModifyVariable
• @Implements
• @Slice
• @Mutable, @Final (Mixin Cleaner)

We don't support:

• @ModifyArg, @ModifyArgs

[jamierocks]

To add onto that, with regards to @Mixin - we currently do not support multiple targets.

[jamierocks]

Mixin 0.8.3 snapshots are out, and we have a new annotation to support:

• @Desc