fix: use correct specifier

Author: headlessNode

lib/node_modules/@stdlib/blas/ext/base/dnannsumkbn/README.md

@@ -278,7 +278,7 @@ int main( void ) {
 
     // Print the result:
     printf( "sum: %lf\n", v );
-    printf( "n: %d\n", n );
+    printf( "n: %ld\n", n );
 }
 ```
 

lib/node_modules/@stdlib/blas/ext/base/dnannsumkbn/examples/c/example.c

@@ -38,5 +38,5 @@ int main( void ) {
 
 	// Print the result:
 	printf( "sum: %lf\n", v );
-	printf( "n: %d\n", n );
+	printf( "n: %ld\n", n );
 }