[DUX-1295] Linebreaks between log messages

[9999years]

The ghcid-ng logging code was adapted from the bootstrap-mercury logging code, which prints one-line log messages on a single line, but places a linebreak before and after long log messages (which get wrapped onto multiple lines).

Unfortunately, this doesn't work super well with ghcid-ng, where log messages are interspersed with forwarded output from the underlying ghci session. This causes line breaks to be weird and nonsensical.

The easiest way forward is probably to just remove the linebreaks before and after long messages.

_{From SyncLinear.com | DUX-1295}

[9999years]

I'm going to fix this as part of making the tracing formatter its own crate (tracing-human-layer).