P1673: "whose type is a template parameter with Out in its name" is outdated

[mhoemmen]

cpp-proposals-pub/D1673/P1673.md

Line 5630 in d8f530f

whose type is a template parameter with `Out` in its name,

([linalg.general]) speak of "a function parameter whose type is a template parameter with Out in its name." We have exposition-only concepts now to talk about output and in/out parameters, so this language is likely outdated.