bench: refactor to use string interpolation in stats/base/ndarray/nanmeanpn

---
type: pre_commit_static_analysis_report
description: Results of running static analysis checks when committing changes.
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---

Author: Om-A-osc

lib/node_modules/@stdlib/stats/base/ndarray/nanmeanpn/benchmark/benchmark.js

@@ -27,6 +27,7 @@ var filledarrayBy = require( '@stdlib/array/filled-by' );
 var isnan = require( '@stdlib/math/base/assert/is-nan' );
 var pow = require( '@stdlib/math/base/special/pow' );
 var ndarray = require( '@stdlib/ndarray/base/ctor' );
+var format = require( '@stdlib/string/format' );
 var pkg = require( './../package.json' ).name;
 var nanmeanpn = require( './../lib' );
 
@@ -109,7 +110,7 @@ function main() {
 	for ( i = min; i <= max; i++ ) {
 		len = pow( 10, i );
 		f = createBenchmark( len );
-		bench( pkg+':len='+len, f );
+		bench( format( '%s:len=%d', pkg, len ), f );
 	}
 }