add eslint rule for requiring semicolons, and then fixing the same issue in the code base

.eslintrc.json

@@ -12,6 +12,7 @@
     "rules": {
         "no-console": "off",
         "no-trailing-spaces": "error",
-        "no-unused-vars": ["error", {"varsIgnorePattern": "ignore"}]
+        "no-unused-vars": ["error", {"varsIgnorePattern": "ignore"}],
+        "semi": ["error", "always"]
     }
 }

add-on/background_scripts/background.js

@@ -180,7 +180,7 @@
             url: details.url,
             name: constants.cookieName,
             value: encodedOptions
-        })
+        });
 
         return {
             responseHeaders: details.responseHeaders

test/functional/lib/utils.js

@@ -19,7 +19,7 @@ module.exports.constants = {
 
 module.exports.pause = function (ms = 2000) {
     return new Promise(function (resolve) {
-        setTimeout(resolve, ms)
+        setTimeout(resolve, ms);
     });
 };
 
@@ -63,7 +63,7 @@ module.exports.promiseExtensionConfigPage = function (driver) {
             const extensionId = match[1];
             driver.setContext(Context.CONTENT);
             return driver.get(`moz-extension://${extensionId}/config/index.html`);
-        })
+        });
 };
 
 module.exports.promiseAddonConfigButton = function (driver) {

test/functional/logins.js

@@ -1,7 +1,7 @@
 "use strict";
 
 const utils = require("./lib/utils");
-let testParams
+let testParams;
 try {
     testParams = require("../../test.config.js");
 } catch (e) {