[array.creation] Clarify "Mandates" for to_array overloads (#7286)

It's confusing that these `to_array` overloads require `T` to be constructible from various types, when they actually construct `remove_cv_t<T>` objects. We experts know that initialization doesn't depend on the cv-qualification of the target type ([dcl.init.general]/16), but there's no need to make readers jump through hoops to understand the spec.

Author: CaseyCarter

source/containers.tex

@@ -6460,7 +6460,7 @@
 \pnum
 \mandates
 \tcode{is_array_v<T>} is \tcode{false} and
-\tcode{is_constructible_v<T, T\&>} is \tcode{true}.
+\tcode{is_constructible_v<remove_cv_t<T>, T\&>} is \tcode{true}.
 
 \pnum
 \expects
@@ -6481,7 +6481,7 @@
 \pnum
 \mandates
 \tcode{is_array_v<T>} is \tcode{false} and
-\tcode{is_move_constructible_v<T>} is \tcode{true}.
+\tcode{is_constructible_v<remove_cv_t<T>, T>} is \tcode{true}.
 
 \pnum
 \expects