docs: document dtype option

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

Author: kgryte

lib/node_modules/@stdlib/ndarray/flatten/lib/main.js

@@ -54,6 +54,7 @@ var COL_MAJOR = 'column-major';
 * @param {Options} [options] - function options
 * @param {NonNegativeInteger} [options.depth] - maximum number of dimensions to flatten
 * @param {string} [options.order='row-major'] - order in which input ndarray elements should be flattened
+* @param {*} [options.dtype] - output ndarray data type
 * @throws {TypeError} first argument must be an ndarray-like object
 * @throws {TypeError} options argument must be an object
 * @throws {TypeError} must provide valid options
@@ -296,8 +297,8 @@ function flatten( x, options ) {
 
 	// Define default options:
 	opts = {
-		'depth': xsh.length, // by default, flatten to a one-dimensional ndarray
-		'order': ROW_MAJOR,   // by default, flatten in lexicographic order (i.e., trailing dimensions first; e.g., if `x` is a matrix, flatten row-by-row)
+		'depth': xsh.length,    // by default, flatten to a one-dimensional ndarray
+		'order': ROW_MAJOR,     // by default, flatten in lexicographic order (i.e., trailing dimensions first; e.g., if `x` is a matrix, flatten row-by-row)
 		'dtype': getDType( x )
 	};