docs: added NaN value in examples

---
type: pre_push_report
description: Results of running various checks prior to pushing changes.
report:
  - task: run_javascript_examples
    status: na
  - task: run_c_examples
    status: na
  - task: run_cpp_examples
    status: na
  - task: run_javascript_readme_examples
    status: failed
---

Author: 0PrashantYadav0

lib/node_modules/@stdlib/stats/base/dnanvariancech/README.md

@@ -136,7 +136,7 @@ Note that indexing is relative to the first index. To introduce an offset, use [
 ```javascript
 var Float64Array = require( '@stdlib/array/float64' );
 
-var x0 = new Float64Array([2.0, 1.0, 2.0, -2.0, -2.0, 2.0, 3.0, 4.0, NaN, NaN]);
+var x0 = new Float64Array( [ 2.0, 1.0, 2.0, -2.0, -2.0, 2.0, 3.0, 4.0, NaN, NaN ] );
 var x1 = new Float64Array( x0.buffer, x0.BYTES_PER_ELEMENT*1 ); // start at 2nd element
 
 var v = dnanvariancech( 5, 1, x1, 2 );
@@ -165,9 +165,9 @@ While [`typed array`][mdn-typed-array] views mandate a view offset based on the
 ```javascript
 var Float64Array = require( '@stdlib/array/float64' );
 
-var x = new Float64Array( [ 2.0, 1.0, 2.0, -2.0, -2.0, 2.0, 3.0, 4.0 ] );
+var x = new Float64Array( [ 2.0, 1.0, 2.0, -2.0, -2.0, 2.0, 3.0, 4.0, NaN, NaN ] );
 
-var v = dnanvariancech.ndarray( 4, 1, x, 2, 1 );
+var v = dnanvariancech.ndarray( 5, 1, x, 2, 1 );
 // returns 6.25
 ```