feat: update blas/base/ndarray TypeScript declarations

PR-URL: #11275
Reviewed-by: Athan Reines <kgryte@gmail.com>
Reviewed-by: Philipp Burckhardt <pburckhardt@outlook.com>

Author: stdlib-bot

lib/node_modules/@stdlib/blas/base/ndarray/docs/types/index.d.ts

@@ -22,6 +22,7 @@
 
 import dasum = require( '@stdlib/blas/base/ndarray/dasum' );
 import ddot = require( '@stdlib/blas/base/ndarray/ddot' );
+import gasum = require( '@stdlib/blas/base/ndarray/gasum' );
 import gdot = require( '@stdlib/blas/base/ndarray/gdot' );
 import sasum = require( '@stdlib/blas/base/ndarray/sasum' );
 import sdot = require( '@stdlib/blas/base/ndarray/sdot' );
@@ -69,6 +70,23 @@ interface Namespace {
 	*/
 	ddot: typeof ddot;
 
+	/**
+	* Computes the sum of absolute values for all elements in a one-dimensional ndarray.
+	*
+	* @param arrays - array-like object containing a one-dimensional input ndarray
+	* @returns sum
+	*
+	* @example
+	* var ndarray = require( '@stdlib/ndarray/base/ctor' );
+	*
+	* var xbuf = [ 1.0, -2.0, 3.0, -4.0, 5.0 ];
+	* var x = new ndarray( 'generic', xbuf, [ 5 ], [ 1 ], 0, 'row-major' );
+	*
+	* var y = ns.gasum( [ x ] );
+	* // returns 15.0
+	*/
+	gasum: typeof gasum;
+
 	/**
 	* Computes the dot product of two one-dimensional ndarrays.
 	*