Added a few touchups in terms of input

[memory-hunter]

Changes

• Added usage text:

  "Usage: nmuidi <dir> (-y)"

• Added passing argument -y to skip confirmation. This was motivated by the README saying that the program doesn't confirm and from the default rm command output in Powershell:

  Confirm
  The item at C:\Users\MemoryHunter\Desktop\New folder\ has children and the Recurse parameter was not specified. If you
  continue, all children will be removed with the item. Are you sure you want to continue?
  [Y] Yes  [A] Yes to All  [N] No  [L] No to All  [S] Suspend  [?] Help (default is "Y"):

  as this requires confirmation, thought since this was meant to speed up operations on Windows, it deserves the same sort of behaviour as the rm in Powershell.

What to improve

I am not quite sure how to add tests properly for the behaviours I added, so that's needed.

[memory-hunter]

I assumed the program took no more than one directory. Fixing the code according to that.

[brasky]

I appreciate the effort but I do not want to add a confirmation message to the tool. Anyone using this tool should be aware that it will not check in with you after you hit enter and you should be careful.