Replace spaces with dashes when naming branches

[zachrammell]

This is a small quality-of-life change to make using the New Branch and Rename Branch menus feel more natural. Since spaces in branch names are invalid, this will interactively replace spaces with dashes while typing, ensuring that the input remains valid.

[jorio]

Good idea, and I appreciate the test!

I suggest installing a QValidator into the QLineEdit. This way we don't need to fiddle with the cursor.

class ReplaceSpacesWithDashes(QValidator):
    def validate(self, text: str, pos: int) -> tuple[QValidator.State, str, int]:
        text = text.replace(" ", "-")
        return QValidator.State.Acceptable, text, pos

...
...nameEdit.setValidator(...)

Also, please avoid editing ui_newbranchdialog.py, because it's automatically generated from newbranchdialog.ui, so any manual changes may be overwritten in the future (after I edit a form in Qt Designer, I regenerate the ui_*.py files in bulk with update_resources.py --ui).

Feel free to connect any signals/validators in newbranchdialog.py instead!