chore: use const/let instead of var

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

Author: Planeshifter

lib/node_modules/@stdlib/blas/ext/base/dnansum/README.md

@@ -43,9 +43,9 @@ Computes the sum of double-precision floating-point strided array elements, igno
 ```javascript
 const Float64Array = require( '@stdlib/array/float64' );
 
-var x = new Float64Array( [ 1.0, -2.0, NaN, 2.0 ] );
+const x = new Float64Array( [ 1.0, -2.0, NaN, 2.0 ] );
 
-var v = dnansum( x.length, x, 1 );
+const v = dnansum( x.length, x, 1 );
 // returns 1.0
 ```
 
@@ -89,7 +89,7 @@ const Float64Array = require( '@stdlib/array/float64' );
 
 const x = new Float64Array( [ 1.0, -2.0, NaN, 2.0 ] );
 
-var v = dnansum.ndarray( x.length, x, 1, 0 );
+const v = dnansum.ndarray( x.length, x, 1, 0 );
 // returns 1.0
 ```