Don't need to print that ever
Rename line, add docstring, add guards
Use the now renamed format-line-info
Ditch unused :refer symbols
Document -step-reach-set
Tweak global-reach-set, type is really a parameter
Tweak tree-shake's docstring & add preconditions
Missed an instance of util/line
Update trim-with-emit-set's docstring & :pre forms