[feature request] open file(s) specifed on cmdline in existing session (by default?), same as gedit without --new-window or --standalone

[Mis012]

This is important for certain workflows, and shouldn't be too hard to implement (GApplication has provisions for this, which I assume are what gedit uses)

Related to this, there should be an option to open the new file(s) in tabs (this would also apply to specifying multiple files to open in a new session)

It doesn't need to be the default, even a cmdline option would be fine since alias exists