Language Files for GTK Source View compatible editors (gedit)
These are easy to install, just download the file and install in ~/.local/share/gtksourceview-3.0/language-specs for personal use (You may need to create the directory). Install it in /usr/local/share/gtksourceview-3.0/language-specs for system-wide use.
After installing you need to restart your editor for it to appear as a syntax option.