In NVDA's voice settings, a synthesizer can implement specific settings, such as inflection, etc. For this, the VoiceSettingsSlider class is available for use. I propose generalizing this custom settings system to allow custom settings for braille displays as well. Possibilities include:

• Dot firmness
• Enable/disable braille input. This is desirable for the handy tech driver, since one of the handy tech devices uses the space keys for either scrolling or braille input
• Enable/disable active tactile control, also for Handy Tech devices

CC @bramd