New set of available keys (Ctrl, Alt)

[fcsonline]

A part of the common tmux-thumbs hints + the shift ones, we want to introduce a new set of combinations with ctrl and alt keys.

This is a breaking change because the configuration options has been renamed.

[deejayem]

Is there any chance of this being completed/merged?

By the way, usually when things are marked as deprecated, they aren't removed yet. This lets people know that they should no longer use them, and that they might be removed in the future. If you implemented the change that way, then it wouldn't be a breaking change (but potentially the code would be messier).