bench: refactor to use string interpolation in array/base/bifurcate-indices

PR-URL: #8851
Ref: #8647

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

Author: ashutoshsao

lib/node_modules/@stdlib/array/base/bifurcate-indices/benchmark/benchmark.length.js

@@ -25,6 +25,7 @@ var pow = require( '@stdlib/math/base/special/pow' );
 var isArrayArray = require( '@stdlib/assert/is-array-array' );
 var discreteUniform = require( '@stdlib/random/array/discrete-uniform' );
 var zeroTo = require( '@stdlib/array/base/zero-to' );
+var format = require( '@stdlib/string/format' );
 var pkg = require( './../package.json' ).name;
 var bifurcateIndices = require( './../lib' );
 
@@ -97,7 +98,7 @@ function main() {
 		len = pow( 10, i );
 
 		f = createBenchmark( len );
-		bench( pkg+':len='+len, f );
+		bench( format( '%s:len=%d', pkg, len ), f );
 	}
 }