bench: refactor to use string interpolation in array/base/filled2d

PR-URL: #8902
Ref: #8647

Co-authored-by: Philipp Burckhardt <[email protected]>
Reviewed-by: Philipp Burckhardt <[email protected]>
Signed-off-by: Philipp Burckhardt <[email protected]>

Author: JavaTypedScript

lib/node_modules/@stdlib/array/base/filled2d/benchmark/benchmark.size.js

@@ -25,6 +25,7 @@ var pow = require( '@stdlib/math/base/special/pow' );
 var floor = require( '@stdlib/math/base/special/floor' );
 var sqrt = require( '@stdlib/math/base/special/sqrt' );
 var isArrayArray = require( '@stdlib/assert/is-array-array' );
+var format = require( '@stdlib/string/format' );
 var pkg = require( './../package.json' ).name;
 var filled2d = require( './../lib' );
 
@@ -89,7 +90,7 @@ function main() {
 		N = floor( sqrt( pow( 10, i ) ) );
 
 		f = createBenchmark( N );
-		bench( pkg+'::square_matrix:size='+(N*N), f );
+		bench( format( '%s::square_matrix:size=%d', pkg, N*N ), f );
 	}
 }