swift234

Demangle: Tweak how dependent types are demangled to make them look more like archetypes.

Share the logic we use to map archetype depth-index pairs to friendly unique names like 'A', 'B', so that demangle generic signatures are still somewhat readable, and so that archetype references into outer contexts with interface type manglings still make sense. Change the remangler to mangle archetypes and dependent generic params using nested index nodes instead of trying to parse the depth and index from the arbitrary names we give them.

Swift SVN r28343