Make Ctrl+(Shift+)Tab focus out of the terminal like it does for GtkTextView
As (Shift+)Tab is already widely used by terminal programs, the situation with getting the focus out of the terminal from the keyboard is similar to the one with the GtkTextView, where it instead is possible to move focus out from it using Ctrl+(Shift+)Tab. So I wonder if it would be possible to have the same behavior for the VteTerminal, so that it's actually possible to use a VteTerminal in an application that's not entirely composed of a single terminal (i.e. not GNOME Terminal, more like GNOME Builder w/ its terminal pages) without breaking keyboard focus. In Builder this is currently quite of an issue, as terminals grab pretty much every shortcuts one might do (unless all shortcuts are set to the capture phase of course, which isn't ideal), so having a way of moving the focus out of the terminal would help solve a bit this problem, and actually allow moving properly the focus with only the keyboard without needing to close terminals that are reached when moving the focus. I don't think it's unreasonable to be prevent terminal programs from using Ctrl+(Shift+)Tab, as they already have the full range of shortcuts available to them, so at some point there must be some clean way of "escaping" from a terminal widget.