It looks like Sublime and Nano support syntax highlighting for Bro IDS:
Is anyone aware of other text editors that also have syntax highlighting support? It would be awesome to see bro language syntax highlighting supported in gVim or notepad++ .
We also have an official Pygments lexer  which you may use to as a
reference. Github uses to it highlight Bro code.
I used Matthias’ pygments submission for Bro to do some of the syntax highlighting for the emacs bro-mode