P1673: "the value_type type alias of any input or output mdspan parameter(s)..."

[mhoemmen]

cpp-proposals-pub/D1673/P1673.md

Line 5709 in d8f530f

of any input or output `mdspan` parameter(s)

[linalg.reqs.val] refers to "the value_type type alias of any input or output mdspan parameter(s) of any function in [linalg]." We should be able to omit "input or output" here, and thus avoid (a) what about in/out parameters?, and (b) needing to refer to the not-yet-defined exposition-only concepts.