chore: fix error in example and docs

Author: anxhukumar

lib/node_modules/@stdlib/stats/incr/nanmmaxabs/README.md

@@ -92,7 +92,6 @@ m = accumulator();
 ## Examples
 
 <!-- eslint no-undef: "error" -->
-
 ```javascript
 var uniform = require( '@stdlib/random/base/uniform' );
 var bernoulli = require( '@stdlib/random/base/bernoulli' );

lib/node_modules/@stdlib/stats/incr/nanmmaxabs/examples/index.js

@@ -33,5 +33,5 @@ var i;
 for ( i = 0; i < 100; i++ ) {
 	v = ( bernoulli( 0.8 ) < 1 ) ? NaN : uniform( -100.0, 100.0 );
 	m = accumulator( v );
-	console.log( '%d\t%d', v.toFixed( 3 ), ( mu === null ) ? NaN : m.toFixed( 3 ) );
+	console.log( '%d\t%d', v.toFixed( 3 ), ( m === null ) ? NaN : m.toFixed( 3 ) );
 }