Document easier solution to jaw remaining open issue

[wilg]

Here's an explanation of a much easier and faster way to fix the jaw issue with certain animations: https://crazyminnowstudio.com/docs/salsa-lip-sync/modules/further-reading/working-with-mecanim-other-influencers/#model-jaw-remains-open

Select the model in the Project.
Switch to the 'Rig' tab.
Click 'Configure'.
avatar rig config
Switch to 'Mapping' tab.
Switch to 'Head' mapping.
Remove the 'Jaw' link.
avatar jaw mapping