js: Use inside variant of IIFE wrappers.

Prettier would do this anyway, but it’s separated out for a more
reviewable diff.  Generated by ESLint.

Signed-off-by: Anders Kaseorg <anders@zulip.com>

static/js/resize.js

@@ -144,12 +144,12 @@ exports.watch_manual_resize = function (element) {
         document.body.addEventListener("mouseup", body_handler);
 
         return [box_handler, body_handler];
-    }((height) => {
+    })((height) => {
         // This callback disables autosize on the textarea.  It
         // will be re-enabled when this component is next opened.
         autosize.destroy($(element))
             .height(height + "px");
-    }));
+    });
 };
 
 exports.resize_bottom_whitespace = function (h) {