improve .desktop file

[Nukleari]

A few suggestions to improve the included desktop entry:

1. add categories ex.: Categories=Utility;TextEditor;
2. add a more complete list of media types ex.: MimeType=text/english;text/plain;text/x-makefile;text/x-c++hdr;text/x-c++src;text/x-chdr;text/x-csrc;text/x-java;text/x-moc;text/x-pascal;text/x-tcl;text/x-tex;application/x-shellscript;text/x-c;text/x-c++; (this is the exact list of media types used in other editors like vim or Helix)
3. replace %U with %F as it better represents the arguments edit expects (correct me if I'm wrong but as far as I know only files work here not urls)

• One extra thing is about using edit as the icon name, on my system some other edit icon was picked up by wofi from some other package that's meant to represent some other ui element to edit something. (I'm not saying it needs to be changed, as naming is different on different distros, but it could be a common conflict. I have a slight bias in this regard as an arch user, I would prefer msedit to be used for both the icon and executable names here)

P.S. I am also discussing including a .desktop file in the arch package, and the maintainers would like to avoid making one and would like to use the one included here.