Compression error hints can make wrong suggestions

[marcospb19]

Originally posted by @dcariotti in #84 (comment)

Problem

After running this:

ouch c 1.txt 2.txt archive.lz.tar

Ouch shows an error message:

[ERROR] Cannot compress to 'archive.lz.tar'.
 - You are trying to compress multiple files.
 - The compression format '.lz' cannot receive multiple files.
 - The only supported formats that archive files into an archive are .tar and .zip.

hint: Try inserting '.tar' or '.zip' before '.lz'.
hint: From: archive.lz.tar
hint:  To : archive.tar.lz.tar

However, if you follow what the hints suggest and use archive.tar.lz.tar:

ouch c 1.txt 2.txt archive.tar.lz.tar

You will receive the following error:

 - Found the format '.tar' in an incorrect position.
 - '.tar' can only be used at the start of the file extension.

hint: If you wish to compress multiple files, start the extension with '.tar'.
hint: Otherwise, remove '.tar' from 'archive.tar.lz.tar'.

---

Our hints are not ready for this specific errors.

Maybe it probably should just have said "you might want to move .tar to the start".

There are actually a lot of ways we can rethink those error messages to fix this issue, I'm not currently sure what's the best one.