Append new line between records when using custom --format

[adelplanque]

According to the documentation, when using the --format option, each error report must end with a new line, which is not the case.

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[adelplanque]

I just saw #55, but in #54 only deletion of \r was requested.
All lint tools I know use a breakline between error reports. The standard under Unix is a simple \n. That's why I think it would be a good idea to restore a \n at the end of each error.
Even if we obtain the same effect with {{"\n"}}, this seems to me a tricky way of proceeding for someone who does not know the Go language.
A better solution might be to add \r\n or \n depending on the OS.