the "Opening the file(s) in the existing window of ReText" feature fails if different directory

[hydrargyrum]

have 3 md files:

• foo.md
• subdir/bar.md
• subdir/baz.md

then

• open a shell
• run retext subdir/bar.md &: it works
• run retext baz.md &: it works, but it shouldn't, because baz.md is not in current directory, but in subdir/baz.md
• run retext foo.md &: it doesn't work, but it should, because foo.md is in current directory

if the filename given on command-line is relative, it should be fully resolved by the new retext process before sending it via IPC to the existing retext process, instead of being resolved in the existing process relatively to currently open file