* Make handleDtsMayChangeOf void-returning
Right now, it always returns false. This seems important, since
otherwise it would stop graph traversals prematurely. It took me a
while to figure that out though and I thought it might be clearer if it
were simply void-returning.
I've kept the behavior the same, except in
`forEachReferencingModulesOfExportOfAffectedFile`, where it seemed like
never enqueueing new references was a mistake.
* Make forEachFileAndExportsOfFile void-returning
As far as I can tell, it could only return `false`.
cdd7ffdc56