Tilt filter parameter for Freeverb

[CSumm]

The feature you'd like
An option to add a tilt filter on the Freeverb constructor to add colour to reverb tail, whether brightness or darkness.

Any alternatives you've considered
Tried creating a Freeverb with tilt filter option using Web Audio API and it half worked where tilt filter did work on tail, but the reverb properties couldn't be adjusted. Having this option in ToneJS would save time creating this feature (like a plate reverb bright and dark knob)

Additional context
Tried it myself with default Web Audio API, could not get it exactly working as expected, discovered that ToneJS has a Freeverb option and decided to pitch the idea.

[github-actions]

Unfortunately with limited development time, not all feature requests can be tackled. If you are interested in contributing this feature, please open a PR.