[func.wrap.move.class, func.wrap.copy.class] Fix singular and plural in subclause titles (#8232)

Author: hewillk

source/utilities.tex

@@ -14123,7 +14123,7 @@
   public:
     using result_type = R;
 
-    // \ref{func.wrap.move.ctor}, constructors, assignment, and destructor
+    // \ref{func.wrap.move.ctor}, constructors, assignments, and destructor
     move_only_function() noexcept;
     move_only_function(nullptr_t) noexcept;
     move_only_function(move_only_function&&) noexcept;
@@ -14170,7 +14170,7 @@
 for which \tcode{is_nothrow_move_constructible_v<T>} is \tcode{true}.
 \end{note}
 
-\rSec4[func.wrap.move.ctor]{Constructors, assignment, and destructor}
+\rSec4[func.wrap.move.ctor]{Constructors, assignments, and destructor}
 
 \indextext{move_only_function::is-callable-from@\tcode{move_only_function::\exposid{is-callable-from}}}%
 \begin{itemdecl}
@@ -14516,7 +14516,7 @@
   public:
     using result_type = R;
 
-    // \ref{func.wrap.copy.ctor}, constructors, assignments, and destructors
+    // \ref{func.wrap.copy.ctor}, constructors, assignments, and destructor
     copyable_function() noexcept;
     copyable_function(nullptr_t) noexcept;
     copyable_function(const copyable_function&);
@@ -14565,7 +14565,7 @@
 for which \tcode{is_nothrow_move_constructible_v<T>} is \tcode{true}.
 \end{note}
 
-\rSec4[func.wrap.copy.ctor]{Constructors, assignments, and destructors}
+\rSec4[func.wrap.copy.ctor]{Constructors, assignments, and destructor}
 
 \indextext{copyable_function::is-callable-from@\tcode{copyable_function::\exposid{is-callable-from}}}%
 \begin{itemdecl}