If you use Vim, there are a few projects with syntax highlighting support for TianoCore sources and config files. A recent one, from this year:
Two others from 2013, with different features from above one:
If you use Visual Slick Edit, one firmware engineer at Dell has created some files for EDK-II support:
I found no support found for Emacs, perhaps the FSF anti-UEFI campaign has impacted this? I don’t know of any EDK-II support in any other open source programmer’s editors or IDEs.
Besides highlighting C/assembly sources, EDK2 has 7 different build/config files, much more complex than a single Makefile to deal with. The specs for these files are listed below; it would be nice if you spend time in EDK2 sources, if your editor helps you understand these formats.