--appimage-extract should not write info to STDERR

[HaleTom]

When using --appimage-extract, information on the filenames extracted is written on STDERR.

This means that I can't suppress the informational messages while still seeing any errors.

Can it write informational text to STDERR instead?

[TheAssassin]

Seems fair. PRs welcome.

[probonopd]

I think it's a matter of changing

AppImageKit/src/runtime.c

Line 334 in 535139e

fprintf(stderr, "%s\n", prefixed_path_to_extract);

to stdout, isn't it?

[TheAssassin]

Seems so.