Various small fixes relative to the ingress paper

[range.istream.view] Do not repeat declaration of function istream_view
[range.elements.iterator] Renamed from [range.elements_view.iterator]
[range.elements.iterator] Use local typedef difference_type
[range.elements.iterator] Use reference return type for compound assignment

Author: jensmaurer

source/ranges.tex

@@ -5509,9 +5509,6 @@
     basic_istream<CharT, Traits>* stream_{};            // \expos
     Val object_ = Val();                                // \expos
   };
-
-  template<class Val, class CharT, class Traits>
-  basic_istream_view<Val, CharT, Traits> istream_view(basic_istream<CharT, Traits>& s);
 }
 \end{codeblock}
 
@@ -5775,7 +5772,7 @@
 Equivalent to: \tcode{return base_;}
 \end{itemdescr}
 
-\rSec3[range.elements_view.iterator]{Class template \tcode{elements_view::iterator}}
+\rSec3[range.elements.iterator]{Class template \tcode{elements_view::iterator}}
 
 \begin{codeblock}
 namespace std::ranges {
@@ -5842,10 +5839,10 @@
     constexpr friend difference_type operator-(const iterator& x, const iterator& y)
       requires RandomAccessRange<base_t>;
 
-    constexpr friend range_difference_t<base_t>
+    constexpr friend difference_type
       operator-(const iterator<Const>& x, const sentinel_t<base_t>& y)
         requires SizedSentinel<sentinel_t<base_t>, iterator_t<base_t>>;
-    constexpr friend range_difference_t<base_t>
+    constexpr friend difference_type
       operator-(const sentinel_t<base_t>& x, const iterator<Const>& y)
         requires SizedSentinel<sentinel_t<base_t>, iterator_t<base_t>>;
   };
@@ -5950,7 +5947,7 @@
 \end{itemdescr}
 
 \begin{itemdecl}
-constexpr iterator operator+=(difference_type n);
+constexpr iterator& operator+=(difference_type n);
   requires RandomAccessRange<base_t>;
 \end{itemdecl}
 
@@ -5965,7 +5962,7 @@
 \end{itemdescr}
 
 \begin{itemdecl}
-constexpr iterator operator-=(difference_type n)
+constexpr iterator& operator-=(difference_type n)
   requires RandomAccessRange<base_t>;
 \end{itemdecl}
 
@@ -6099,19 +6096,19 @@
 \end{itemdescr}
 
 \begin{itemdecl}
-constexpr friend range_difference_t<base_t>
+constexpr friend difference_type
   operator-(const iterator<Const>& x, const sentinel_t<base_t>& y)
     requires SizedSentinel<sentinel_t<base_t>, iterator_t<base_t>>;
 \end{itemdecl}
 
 \begin{itemdescr}
 \pnum
 \effects
-Equivalent to: \tcode{return x.current_ - y};
+Equivalent to: \tcode{return x.current_ - y;}
 \end{itemdescr}
 
 \begin{itemdecl}
-constexpr friend range_difference_t<base_t>
+constexpr friend difference_type
   operator-(const sentinel_t<base_t>& x, const iterator<Const>& y)
     requires SizedSentinel<sentinel_t<base_t>, iterator_t<base_t>>;
 \end{itemdecl}