refactor: improve type specificity

Author: kgryte

lib/node_modules/@stdlib/ndarray/iter/columns/docs/types/index.d.ts

@@ -21,7 +21,7 @@
 /// <reference types="@stdlib/types"/>
 
 import { TypedIterator, TypedIterableIterator } from '@stdlib/types/iter';
-import { ndarray } from '@stdlib/types/ndarray';
+import { typedndarray } from '@stdlib/types/ndarray';
 
 // Define a union type representing both iterable and non-iterable iterators:
 type Iterator<T> = TypedIterator<T> | TypedIterableIterator<T>;
@@ -79,7 +79,7 @@ interface Options {
 *
 * // ...
 */
-declare function nditerColumns( x: ndarray, options?: Options ): Iterator<ndarray>;
+declare function nditerColumns<T = unknown>( x: typedndarray<T>, options?: Options ): Iterator<typedndarray<T>>;
 
 
 // EXPORTS //

lib/node_modules/@stdlib/ndarray/iter/columns/docs/types/test.ts

@@ -24,8 +24,8 @@ import nditerColumns = require( './index' );
 
 // The function returns an iterator...
 {
-	nditerColumns( zeros( [ 2, 2 ] ) ); // $ExpectType Iterator<ndarray>
-	nditerColumns( zeros( [ 2, 2 ] ), {} ); // $ExpectType Iterator<ndarray>
+	nditerColumns( zeros( [ 2, 2 ] ) ); // $ExpectType Iterator<typedndarray<number>>
+	nditerColumns( zeros( [ 2, 2 ] ), {} ); // $ExpectType Iterator<typedndarray<number>>
 }
 
 // The compiler throws an error if the function is provided a first argument which is not an ndarray...