std.mem: fix simd.suggestVectorLength merge conflict

Commits
2f8e4347b1f9c2bf093ac48a636576c22359c1ff and
6a32d58876995f18b35ffd89b8875a99417c29cf had a conflict that was
undetected by source control.
e025ad7b46Andrew Kelley committed on 1/10/2024, 1:20:53 AMparent828d239
1 file changedLine totals unavailable