Fix example return value

Author: kgryte

lib/node_modules/@stdlib/stats/incr/mae/lib/index.js

@@ -32,7 +32,7 @@
 * // returns null
 *
 * m = accumulator( 2.0, 3.0 );
-* // returns 2.0
+* // returns 1.0
 *
 * m = accumulator( -5.0, 2.0 );
 * // returns 4.0