Increase locality of the character encoding used for a given string.

It's currently quite difficult to implement visualization for a given const.str entry as the partition contains several possible character encodings and does not specify what character encoding is used for a particular element of the partition (instead relying upon the context for how the string is referenced (e.g., src.word can reference a const.str entry as a wide character literal while TextOffset contextually means a UTF-8 null-terminated identifier).

I think it would be a significant improvement if there was either a partition per-encoding (e.g., const.utf-8-str, const.utf-16-str, etc, or an encoding specified per line). This similarly would make it harder for folks -- such as myself :) -- to misinterpret the encoding of the contents of the partition.

Start by reviewing the IFC specification sections defining the const.str partition and the src.word and TextOffset references mentioned in the issue. Compare the proposed per-encoding partitions with per-line encoding metadata, then define and document one consistent approach so each string's character encoding is locally identifiable.