[everywhere] Rename exposition-only concept 'same-impl' to 'same-as-impl'.

Author: zygoloid

source/concepts.tex

@@ -276,10 +276,10 @@
 \indexlibrary{\idxcode{same_as}}%
 \begin{itemdecl}
 template<class T, class U>
-  concept @\placeholdernc{same-impl}@ = is_same_v<T, U>;    // \expos
+  concept @\placeholdernc{same-as-impl}@ = is_same_v<T, U>;    // \expos
 
 template<class T, class U>
-  concept same_as = @\placeholdernc{same-impl}@<T, U> && @\placeholdernc{same-impl}@<U, T>;
+  concept same_as = @\placeholdernc{same-as-impl}@<T, U> && @\placeholdernc{same-as-impl}@<U, T>;
 \end{itemdecl}
 
 \begin{itemdescr}