bench: use string interpolation in blas/ext/base/ndarray/gsumkbn

PR-URL: #10353
Ref: #8647

Reviewed-by: Philipp Burckhardt <pburckhardt@outlook.com>

Author: AyushiJain18270

lib/node_modules/@stdlib/blas/ext/base/ndarray/gsumkbn/benchmark/benchmark.js

@@ -25,6 +25,7 @@ var uniform = require( '@stdlib/random/array/uniform' );
 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 gsumkbn = require( './../lib' );
 
@@ -101,7 +102,7 @@ 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 );
 	}
 }