Improve nonexistent input action message when using a Shortcut resource in a Button's Shortcut property

[AlexHolly]

x11
8698876

Is there a way to make the error more specific? (point to the Button/ShortCut)

Steps:

1. Create a Button
2. Add "ShortCut"
3. Add "InputEventAction"
4. Run and press any key

[EricEzaM]

Can't really be done. That message comes from a call to ERR_FAIL_COND_V_MSG in C++ from what I can tell, and that is in InputMap::event_get_action_status. It has no knowledge of the methods that called it and as such could not get information about the button.

Here is the stack trace for where the error is generated:

An option is to GREP your code for the name of the nonexistent action, or open it in something like VS Code and do a project-wide search for the term (as it will also search tscn)

> grep -r dontexist
scene.tscn:action = &"dontexist"

I think this can be closed under "won't do" for now...?