fix: use correct dtype policy

Signed-off-by: Athan <[email protected]>

Author: kgryte

lib/node_modules/@stdlib/stats/nanmean/docs/types/index.d.ts

@@ -21,7 +21,7 @@
 /// <reference types="@stdlib/types"/>
 
 import { ArrayLike } from '@stdlib/types/array';
-import { RealAndGenericDataType as DataType, typedndarray } from '@stdlib/types/ndarray';
+import { RealFloatingPointAndGenericDataType as DataType, typedndarray } from '@stdlib/types/ndarray';
 
 /**
 * Input array.