Provide a user friendly error if the user can't run workbox code

[MHendricks]

If the user hasn't setup a workbox and accidentally uses the keyboard shortcuts to run workbox code it will now provide a error to point them to the correct shortcut.

Checklist

• I have read the CONTRIBUTING.md document
• I formatted my changes with black
• I linted my changes with flake8
• I have added documentation regarding my changes where necessary
• Any pre-existing tests continue to pass
• Additional tests were made covering my changes

Types of Changes

• Bugfix (change that fixes an issue)
• New Feature (change that adds functionality)
• Documentation Update (if none of the other choices apply)

Proposed Changes

The old error message:

Traceback (most recent call last):
  File "[C:\blur\dev\preditor\preditor\gui\loggerwindow.py](c:\blur\dev\preditor\preditor\gui\loggerwindow.py, , 1336)", line 1336, in execAll
    self.current_workbox().__exec_all__()
AttributeError: 'NoneType' object has no attribute '__exec_all__'

The new error message:

Traceback (most recent call last):
  File "C:\blur\dev\preditor\preditor\gui\loggerwindow.py", line 1340, in execAll
    raise RuntimeError(
RuntimeError: You must choose an Editor Class in the workbox section before you can run code from it. (To run console code don't use Shift or Ctrl when pressing Return.)