feat: update complex/float64/base TypeScript declarations

lib/node_modules/@stdlib/complex/float64/base/docs/types/index.d.ts

@@ -21,6 +21,7 @@
 /* eslint-disable max-lines */
 
 import add = require( '@stdlib/complex/float64/base/add' );
+import add3 = require( '@stdlib/complex/float64/base/add3' );
 import assert = require( '@stdlib/complex/float64/base/assert' );
 import div = require( '@stdlib/complex/float64/base/div' );
 import identity = require( '@stdlib/complex/float64/base/identity' );
@@ -70,6 +71,44 @@ interface Namespace {
 	*/
 	add: typeof add;
 
+	/**
+	* Computes the sum of three double-precision complex floating-point numbers.
+	*
+	* @param z1 - first complex number
+	* @param z2 - second complex number
+	* @param z3 - third complex number
+	* @returns result
+	*
+	* @example
+	* var Complex128 = require( '@stdlib/complex/float64/ctor' );
+	*
+	* var z = new Complex128( 5.0, 3.0 );
+	*
+	* var out = ns.add3( z, z, z );
+	* // returns <Complex128>[ 15.0, 9.0 ]
+	*
+	* @example
+	* var Float64Array = require( '@stdlib/array/float64' );
+	*
+	* var out = new Float64Array( 2 );
+	* var v = ns.add3.assign( 5.0, 3.0, 5.0, 3.0, 5.0, 3.0, out, 1, 0 );
+	* // returns <Float64Array>[ 15.0, 9.0 ]
+	*
+	* var bool = ( out === v );
+	* // returns true
+	*
+	* @example
+	* var Float64Array = require( '@stdlib/array/float64' );
+	*
+	* var z1 = new Float64Array( [ 5.0, 3.0 ] );
+	* var z2 = new Float64Array( [ 5.0, 3.0 ] );
+	* var z3 = new Float64Array( [ 5.0, 3.0 ] );
+	*
+	* var out = ns.add3.strided( z1, 1, 0, z2, 1, 0, z3, 1, 0, new Float64Array( 2 ), 1, 0 );
+	* // returns <Float64Array>[ 15.0, 9.0 ]
+	*/
+	add3: typeof add3;
+
 	/**
 	* Base (i.e., lower-level) double-precision complex number assertion functions.
 	*/