This may or may not matter to too many people, but I created an Inform 6 grammar for Atom.
[url=https://atom.io/packages/language-inform6]https://atom.io/packages/language-inform6[/url]
Zarf has already provided an excellent Inform 7 grammar file for Atom. I wanted Inform 6 to have one as well since I still feel I6 has a lot to offer. Atom is a nice, cross-platform free editor.