[range.zip, ranges.cartesian.iterator] Simplify maybe-const<true, Views> to const Views (#5778)

The type `maybe-const<Const, Views>` only appears after `Const &&`
in these cases, so that only the case where `Const` is `true` matters.

Author: hewillk

source/ranges.tex

@@ -9519,8 +9519,7 @@
 
     @\exposid{iterator}@() = default;
     constexpr @\exposid{iterator}@(@\exposid{iterator}@<!Const> i)
-      requires Const && (@\libconcept{convertible_to}@<iterator_t<Views>,
-                                        iterator_t<@\exposid{maybe-const}@<Const, Views>>> && ...);
+      requires Const && (@\libconcept{convertible_to}@<iterator_t<Views>, iterator_t<const Views>> && ...);
 
     constexpr auto operator*() const;
     constexpr @\exposid{iterator}@& operator++();
@@ -9601,8 +9600,7 @@
 
 \begin{itemdecl}
 constexpr @\exposid{iterator}@(@\exposid{iterator}@<!Const> i)
-  requires Const &&
-           (@\libconcept{convertible_to}@<iterator_t<Views>, iterator_t<@\exposid{maybe-const}@<Const, Views>>> && ...);
+  requires Const && (@\libconcept{convertible_to}@<iterator_t<Views>, iterator_t<const Views>> && ...);
 \end{itemdecl}
 
 \begin{itemdescr}
@@ -9887,8 +9885,7 @@
   public:
     @\exposid{sentinel}@() = default;
     constexpr @\exposid{sentinel}@(@\exposid{sentinel}@<!Const> i)
-      requires Const &&
-               (@\libconcept{convertible_to}@<sentinel_t<Views>, sentinel_t<@\exposid{maybe-const}@<Const, Views>>> && ...);
+      requires Const && (@\libconcept{convertible_to}@<sentinel_t<Views>, sentinel_t<const Views>> && ...);
 
     template<bool OtherConst>
       requires (@\libconcept{sentinel_for}@<sentinel_t<@\exposid{maybe-const}@<Const, Views>>,
@@ -9922,8 +9919,7 @@
 
 \begin{itemdecl}
 constexpr @\exposid{sentinel}@(@\exposid{sentinel}@<!Const> i)
-  requires Const &&
-           (@\libconcept{convertible_to}@<sentinel_t<Views>, sentinel_t<@\exposid{maybe-const}@<Const, Views>>> && ...);
+  requires Const && (@\libconcept{convertible_to}@<sentinel_t<Views>, sentinel_t<const Views>> && ...);
 \end{itemdecl}
 
 \begin{itemdescr}
@@ -14479,8 +14475,8 @@
     @\exposid{iterator}@() requires @\libconcept{forward_range}@<@\exposid{maybe-const}@<Const, First>> = default;
 
     constexpr @\exposid{iterator}@(@\exposid{iterator}@<!Const> i) requires Const &&
-      (@\libconcept{convertible_to}@<iterator_t<First>, iterator_t<@\exposid{maybe-const}@<Const, First>>> &&
-        ... && @\libconcept{convertible_to}@<iterator_t<Vs>, iterator_t<@\exposid{maybe-const}@<Const, Vs>>>);
+      (@\libconcept{convertible_to}@<iterator_t<First>, iterator_t<const First>> &&
+        ... && @\libconcept{convertible_to}@<iterator_t<Vs>, iterator_t<const Vs>>);
 
     constexpr auto operator*() const;
     constexpr @\exposid{iterator}@& operator++();
@@ -14668,8 +14664,8 @@
 
 \begin{itemdecl}
 constexpr @\exposid{iterator}@(@\exposid{iterator}@<!Const> i) requires Const &&
-  (@\libconcept{convertible_to}@<iterator_t<First>, iterator_t<@\exposid{maybe-const}@<Const, First>>> &&
-    ... && @\libconcept{convertible_to}@<iterator_t<Vs>, iterator_t<@\exposid{maybe-const}@<Const, Vs>>>);
+  (@\libconcept{convertible_to}@<iterator_t<First>, iterator_t<const First>> &&
+    ... && @\libconcept{convertible_to}@<iterator_t<Vs>, iterator_t<const Vs>>);
 \end{itemdecl}
 
 \begin{itemdescr}