Apply suggestions from code review

Co-authored-by: Athan <kgryte@gmail.com>
Signed-off-by: Athan <kgryte@gmail.com>

Author: kgryte

lib/node_modules/@stdlib/ndarray/base/rot180/README.md

@@ -103,6 +103,11 @@ var arr = ndarray2array( y );
 y = rot180( x, [ -2, -1 ], false );
 arr = ndarray2array( y );
 // returns [ [ 6, 5, 4 ], [ 3, 2, 1 ] ]
+
+// Rotating twice returns the original arrangement:
+y = rot180( rot180( x, [ 0, 1 ], false ), [ 0, 1 ], false );
+console.log( ndarray2array( y ) );
+// => [ [ 1, 2, 3 ], [ 4, 5, 6 ] ]
 ```
 
 </section>