feat: update doc

Author: adityacodes30

lib/node_modules/@stdlib/array/fixed-endian-factory/README.md

@@ -229,6 +229,27 @@ var len = arr.length;
 
 ### Typed Array Methods
 
+<a name="method-copy-within"></a>
+
+#### TypedArrayFE.prototype.copyWithin( target, start\[, end] )
+
+Copies a sequence of elements within the array starting at `start` and ending at `end` (non-inclusive) to the position starting at `target`.
+
+```javascript
+var Float64ArrayFE = fixedEndianFactory( 'float64' );
+
+var arr = new Float64ArrayFE( 'little-endian', [ 1.0, 2.0, 3.0, 4.0, 5.0 ] );
+
+arr.copyWithin( 0, 3 );
+
+var out = arr.get( 0 );
+// returns 4.0
+
+out = arr.get( 1 );
+// returns 5.0
+```
+
+
 <a name="static-method-from"></a>
 
 #### TypedArrayFE.from( endianness, src\[, map\[, thisArg]] )