log: End diagnostic messages with CRLF if stderr is a terminal
When s-r-launch-client uses SrtPtyBridge, the implementation involves a terminal in raw mode, in which a newline does not imply returning the cursor to the first column, resulting in a "staircase" effect:
I: foo
W: bar
D: baz
Avoid this by explicitly sending a carriage-return character whenever we are logging to a stderr that is a terminal.
Helpful for any use of s-r-launch-client, but I got annoyed enough to implement it as a result of !560 (merged).