Don't write a finishing newline in silent mode

[Nirusu]

Description

When running ffuf in silent mode, a new line is still written on every line at the end of a run of ffuf.
While this looks fine if there are any matches, it will just spam empty new lines whenever:

• No matches are found
• If you redirect stdout but keep stderr on console

Piping ffuf multiple times with different targets, this approx. looks like this:

Screen.Recording.2023-05-10.at.10.25.55.mov

Thus, let's remove printing the new line when in silent mode.

Additonally

• If this is the first time you are contributing to ffuf, add your name to CONTRIBUTORS.md.
  The file should be alphabetically ordered.
• Add a short description of the fix to CHANGELOG.md

-> I skipped since I thought this change is too insignificant.

[joohoi]

Thanks for the PR, merging