Add confirm for nuke if staged changes exist.

**Is your feature request related to a problem? Please describe.**
Just accidentally pressed x instead of u when trying to clean up a commit of some unwanted changes before committing. Deleted a days worth of refactoring work that I have to now redo.

**Describe the solution you'd like**
A simple confirmation prompt instead of executing the command to nuke all my work.

**Describe alternatives you've considered**
I had to go into my vim swap file to recover some of the work. It wasn't all there.

**Additional context**
I immediately knew what happened and yelled "NOOOOO!!!!", as it happened desparately trying to hit escape and q before it executed.