Discoverability of helper functions.

[nojaf]

Context.fs has a plethora of helper functions. Things like sepStar, indentSepNlnUnindent , col, ...

For newcomers, it is currently difficult to know about these. If someone wrote !- "*", we would call it out during a review that sepStar should be used, but for the author of the PR that is somewhat hard to know. We should try to address this problem somehow. Perhaps by splitting them up into multiple files, add XML comments and signature files.

Or by some other means, I don't really know to be honest. Open to suggestions.

//cc @dawedawe