Create reuse addheader --interactive

[carmenbianca]

User story:

The files foo.py and bar.notpy exist in the repo. The user does reuse addheader --copyright Me foo.py bar.notpy. Because at least one file (bar.notpy) has a non-recognised file extension, nothing happens.

Instead, the user can do reuse addheader --interactive --copyright Me foo.py bar.notpy. In this case, the user is prompted about bar.notpy: skip the file? apply a certain comment style? abort? The user is not prompted about foo.py.

[puria]

I would suggest also having the filetype format specified with something like --lang=py or --filetype=py. This would be more scriptable and your shell arrow up (or Ctrl-R) helps more in repetitive times, but the interactive mode should be very useful for the first times, and more annoying some others ;p

[puria]

Oops my bad 😣 seems that --style is exactly what I was looking for