[range.concat.iterator] Improve awkward wording

Author: lprv

source/ranges.tex

@@ -9474,9 +9474,8 @@
 \begin{codeblock}
 (noexcept(ranges::swap(*x, *y)) && ... && noexcept(ranges::iter_swap(its, its)))
 \end{codeblock}
-where \tcode{its} is a pack of lvalues of type
-%FIXME "respectively" doesn't make sense here.
-\tcode{const iterator_t<\exposid{maybe-const}<Const, Views>>} respectively.
+where \tcode{its} is a pack of lvalues of types
+\tcode{const iterator_t<\exposid{maybe-const}<Const, Views>>...}.
 
 \par % This paragraph is part of the \remarks clause.
 The expression in the \grammarterm{requires-clause} is equivalent to