lint: Enforce semicolon spacing in eslint.

We only had a few exceptions to this rule; the zjquery one was actually a bug.

.eslintrc.json

@@ -384,6 +384,7 @@
         "quotes": [ 0, "single" ],
         "radix": 2,
         "semi": 2,
+        "semi-spacing": [2, {"before": false, "after": true}],
         "space-before-blocks": 2,
         "space-before-function-paren": [ "error",
             {

frontend_tests/zjsunit/zjquery.js

@@ -210,7 +210,7 @@ exports.make_new_elem = function (selector, opts) {
         },
         focusout: function () {
             focused = false;
-            return ;
+            return self;
         },
         get: function (idx) {
             // We have some legacy code that does $('foo').get(0).

static/js/message_edit.js

@@ -392,7 +392,8 @@ function edit_message(row, raw_content) {
 
     // Scroll to keep the message content in the same place
     var edit_top = message_edit_content[0].getBoundingClientRect().top;
-    var scroll_by = edit_top - content_top + 5 /* border and padding */;
+    /* adjust for border and padding */
+    var scroll_by = edit_top - content_top + 5;
     edit_obj.scrolled_by = scroll_by;
     message_viewport.scrollTop(message_viewport.scrollTop() + scroll_by);