LWG4001 iota_view should provide empty

Author: burblebee

source/ranges.tex

@@ -2685,6 +2685,7 @@
     constexpr auto end() const;
     constexpr @\exposid{iterator}@ end() const requires @\libconcept{same_as}@<W, Bound>;
 
+    constexpr bool empty() const;
     constexpr auto size() const requires @\seebelow@;
   };
 
@@ -2902,6 +2903,17 @@
 Equivalent to: \tcode{return \exposid{iterator}\{\exposid{bound_}\};}
 \end{itemdescr}
 
+\indexlibrarymember{empty}{iota_view}%
+\begin{itemdecl}
+constexpr bool empty() const;
+\end{itemdecl}
+
+\begin{itemdescr}
+\pnum
+\effects
+Equivalent to: \tcode{return \exposid{value_} == \exposid{bound_};}
+\end{itemdescr}
+
 \indexlibrarymember{size}{iota_view}%
 \begin{itemdecl}
 constexpr auto size() const requires @\seebelow@;