SE-0494: Add `isIdentical(to:)` Methods for Quick Comparisons to Concrete Types

[sveinhal (Svein Halvor Halvorsen)]

@8675309

It strikes me that isKnown is not the right construct here, since isKnownIdentical == false could also be read as “is known as not identical.” hasKnown seems to convey the underlying meaning better, including the reverse. Maybe a different word altogether from “known” is more appropriate.

Swift already has established the isKnown construct in e.g. isKnownUniquelyReferenced
When something "is known" to have a property, it has that property. But when "is known" is false, it is uncertain if it has that property.

I think most people understand that, and if they don't immediately get the meaning of it, the name has just enough friction for you to pause and reflect and/or investigate the docs, methinks.