docs($interpolate): fix typo

There was missing `JS` at line 141.

Closes #15817

src/ng/interpolate.js

@@ -138,7 +138,7 @@ function $InterpolateProvider() {
      * ```js
      *   var $interpolate = ...; // injected
      *   var exp = $interpolate('Hello {{name | uppercase}}!');
-     *   expect(exp({name:'AngularJS'})).toEqual('Hello ANGULAR!');
+     *   expect(exp({name:'AngularJS'})).toEqual('Hello ANGULARJS!');
      * ```
      *
      * `$interpolate` takes an optional fourth argument, `allOrNothing`. If `allOrNothing` is