Fixes and updates for lilypond-invoke-editor script

[Andrew Bernard]

In 2.23.12 at least, there is an error for gvim (missing comma in list) 
in the lilypond-invoke-editor script, and the column number for geany is 
wrong as it numbers columns from zero not one.

While here, should we drop Atom from the list of editors as it is no 
longer supported and discontinued?

I have fixed these issues. Am I allowed to submit a patch to get this 
incorporated?