Immutable value semantic returns questions from #5434

[josh11b]

These questions were prompted by discussion around proposal #5434 .

How should we spell value form returns at a high level? Should we have

• an explicit marker attached to the return?
• an explicit marker attached to the function declaration? or
• imply this from bound parameters?

If the answer is one of the first two, should the explicit marker leverage the keyword let? If not, what keyword or symbol should be employed here?

If we do pick the keyword let, should we rename terminology to use that keyword as well? And how much terminology?

[chandlerc]

Note that these questions (in addition to some others) were discussed in the open discussion, with notes that folks interested can dig through here: https://docs.google.com/document/d/1Yt-i5AmF76LSvD4TrWRIAE_92kii6j5yFiW-S7ahzlg/edit?tab=t.0#heading=h.uot97ukynlsi