monobit-convert does not return an error code

[hackerb9]

monobit-convert always returns 0 (no error) to the shell even when there was an error. While not high priority, it would be nice if this got fixed at some point to make it easier to use monobit-convert in scripts.

$ monobit-convert hellschreiber/feld-hell-tbs24a-7x14.yaff to foo.png -overwrite
ERROR: No codepoint labels found.
$ echo $?
0