stage1: update fn_key_eql() for @mulAdd() on vectors
stage1: update fn_key_eql() for @mulAdd() on vectors

zig-lang/zig,raulgrell/zig,raulgrell/zig,raulgrell/zig,zig-lang/zig,andrewrk/zig,raulgrell/zig,zig-lang/zig,raulgrell/zig,andrewrk/zig