Shortcut to adjust Playback speed slider

Your idea

Two keyboard shortcuts, Increase/Decrease, the recently introduced playback speed percentage. Suggest Shift Alt I for increase and below it Shift Alt J for decrease sit nicely under the fingers without using arrows which I think should be saved for primary navigation tasks.

Problem to be solved

Blind users find navigating to the mixer and playback panels difficult and some sliders are not very accessible Having shortcuts for many of these would greatly increase our use of them. Most don't use this slider currently as it is hard to get to, but it is a tool that would be extremely useful for blind users learning and working often primarily by ear. Currently I still opt to insert a new tempo mark if I want to hear it slower and then remove that rather than trying to navigate to this slider. See also #20092 for other requested playback/mixer shortcuts.

Prior art

No response

Additional context

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Checklist

• This request follows the guidelines for reporting issues
• I have verified that this feature request has not been logged before, by searching the issue tracker for similar requests

The issue names no files, tests, or entry points. Start by locating the playback speed slider and existing keyboard-shortcut handling; done means Shift+Alt+I increases the playback percentage and Shift+Alt+J decreases it, with both shortcuts usable without navigating to the slider.