After speaking with @kwonoj and others, we think it would be best to rename of to just.

1. It's still terse
2. There's precedent (it was just in RxJS 4 and under, and in other Rx dialects)
3. It's less confusing to read than of
4. IDEs don't color code just like they do of

Thoughts? Questions? Concerns?

The process here would be to:

1. deprecate of, but leave it
2. Add just (of would alias just)