fix norminette error formatters output that was not using newlines

[NiumXp]

This is a hotfix for #482.

If we run norminette in a folder that have more than one file, we will be surprised with an output like this:

a.c: OK! b.c: OK! c.c: OK!

Instead of:

a.c: OK!
b.c: OK!
c.c: OK!