[range.chunk.view.input, range.slide.view] Remove unused name in the deduction guide

Author: hewillk

source/ranges.tex

@@ -11740,7 +11740,7 @@
   };
 
   template<class R>
-    chunk_view(R&& r, range_difference_t<R>) -> chunk_view<views::all_t<R>>;
+    chunk_view(R&&, range_difference_t<R>) -> chunk_view<views::all_t<R>>;
 }
 \end{codeblock}
 
@@ -12702,7 +12702,7 @@
   };
 
   template<class R>
-    slide_view(R&& r, range_difference_t<R>) -> slide_view<views::all_t<R>>;
+    slide_view(R&&, range_difference_t<R>) -> slide_view<views::all_t<R>>;
 }
 \end{codeblock}