Update d0796r1.md

Fixed Listing 1 with correct syntax

Author: Ruyman

affinity/cpp-20/d0796r1.md

@@ -45,15 +45,15 @@ Consider a code example (Listing 1) that uses the C++17 parallel STL algorithm `
 std::valarray<double> a(N);
 
 // Data placement is wrong, so parallel update is slow.
-std::for_each(par, std::begin(a), std::end(a),
-  [=] (double& a_i) { scalar * a_i; });
-
+std::for_each(par, std::begin(a), std::end(a), 
+              [=] (double& a_i) { a_i *= scalar; });
+	      
 // Use future affinity interface to migrate data at next
 // use and move pages closer to next accessing thread.
 ...
 // Faster, because data are local now.
-std::for_each(par, std::begin(a), std::end(a),
-  [=] (double& a) { scalar * a_i; } );
+std::for_each(par, std::begin(a), std::end(a), 
+              [=] (double& a_i) { a_i *= scalar; });
 ```
 *Listing 1: Parallel vector update example*