Smalltalk syntax highlighting (BB-4345)

I have a repo which contains exports from Cuis 4.0 in .pck format, which is essentially the Squeak file-out format. I'd appreciate it if I could get syntax highlighting. Just a would-be-nice-someday kind of thing.

Assuming you can see private repos, fusiongyro/Cuis is one with this content in it. You can also see what this might look like on Github here:

https://github.com/jvuletich/Cuis/blob/master/CuisUpdates/1261-CuisCore-JuanVuletich-2012Apr25-09h17m-jmv.9.cs

Looks a little weird there, to be honest, the string quoting seems to be messed up.

Thanks for your time!