feat: add nanmean, nanmeanors, nanmeanpn, and nanmeanwd to namespace

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---

Author: kgryte

lib/node_modules/@stdlib/stats/array/lib/index.js

@@ -234,6 +234,42 @@ setReadOnly( ns, 'nanmaxBy', require( '@stdlib/stats/array/nanmax-by' ) );
 */
 setReadOnly( ns, 'nanmaxabs', require( '@stdlib/stats/array/nanmaxabs' ) );
 
+/**
+* @name nanmean
+* @memberof ns
+* @readonly
+* @type {Function}
+* @see {@link module:@stdlib/stats/array/nanmean}
+*/
+setReadOnly( ns, 'nanmean', require( '@stdlib/stats/array/nanmean' ) );
+
+/**
+* @name nanmeanors
+* @memberof ns
+* @readonly
+* @type {Function}
+* @see {@link module:@stdlib/stats/array/nanmeanors}
+*/
+setReadOnly( ns, 'nanmeanors', require( '@stdlib/stats/array/nanmeanors' ) );
+
+/**
+* @name nanmeanpn
+* @memberof ns
+* @readonly
+* @type {Function}
+* @see {@link module:@stdlib/stats/array/nanmeanpn}
+*/
+setReadOnly( ns, 'nanmeanpn', require( '@stdlib/stats/array/nanmeanpn' ) );
+
+/**
+* @name nanmeanwd
+* @memberof ns
+* @readonly
+* @type {Function}
+* @see {@link module:@stdlib/stats/array/nanmeanwd}
+*/
+setReadOnly( ns, 'nanmeanwd', require( '@stdlib/stats/array/nanmeanwd' ) );
+
 /**
 * @name nanmin
 * @memberof ns