[ranges.syn] Remove "inline" from constexpr variable template

Author: burblebee

source/ranges.tex

@@ -438,7 +438,7 @@
   class enumerate_view;                                                             // freestanding
 
   template<class View>
-    inline constexpr bool enable_borrowed_range<enumerate_view<View>> =             // freestanding
+    constexpr bool enable_borrowed_range<enumerate_view<View>> =                    // freestanding
       enable_borrowed_range<View>;
 
   namespace views { inline constexpr @\unspecnc@ enumerate = @\unspecnc@; }         // freestanding