Add hint to show "right-click" on a yellow commit in the tree window, will paste hash into console

[donfede]

The game has a useful CLI feature, where the Git hashes associated with each yellow commit icon in the tree sub-window will be pasted into the console by right clicking. This feature makes completing the game via CLI achievable. However, this feature is not explained anywhere.

Not sure if that documentation might best be in a separate "CLI power user popup" hint window, or maybe one of the initial green hint boxes, or some other way. Granted, this is a relatively minor issue.

[blinry]

We're planning a feature that allows level authors to explain more CLI-specific stuff in a section like [cli] – this information would fit there really well, I think! Thanks!