# Should ROS msg/srv files end in a newline?

I was perplexed on a recent commit preview to see this symbol on github after a .srv file with no return:

I posted a question on SO, which turned out to be a duplicate of this one, which enlightened me via this one and a subsequent link in a comment that apparently lines not ending in a newline may not be lines at all!

Re-quoting their POSIX standard citation for convenience:

3.206 Line

A sequence of zero or more non- <newline> characters plus a terminating <newline> character.

I can't find anything stating 1) whether or not any downsides occur to having a newline in .msg files, 2) if it's explicitly permitted (presumably so) or 3) if it's advised to always use them.