This adds `debug_panel::Toggle` which is the same as
`terminal_panel::Toggle` but for the debug panel. It also moves
`debug_panel::{Toggle, ToggleFocus}` to its own `pub mod` for
consistency with other keybinds.
[Related
discussion](https://github.com/zed-industries/zed/discussions/47931#discussion-9404091)
Release Notes:
- Added `debug_panel::Toggle` to show/hide debug panel like
`terminal_panel::Toggle`