Bug 1551829 - Upgrade to ESLint 6.1.0. r=mossop

This picks up various improvements, especially to how configurations are handled and some new rules.

Differential Revision: https://phabricator.services.mozilla.com/D37271

.eslintrc.js

@@ -330,5 +330,49 @@ module.exports = {
       "no-useless-return": "off",
       "no-with": "off",
     }
+  }, {
+    "files": [
+      "browser/components/extensions/ExtensionControlledPopup.jsm",
+      "browser/components/extensions/test/browser/browser_ext_devtools_network.js",
+      "browser/components/extensions/test/browser/browser_ext_tabs_zoom.js",
+      "browser/components/places/tests/browser/browser_bookmarksProperties.js",
+      "browser/components/preferences/in-content/tests/browser_extension_controlled.js",
+      "browser/extensions/formautofill/FormAutofillParent.jsm",
+      "browser/tools/mozscreenshots/head.js",
+      "devtools/client/aboutdebugging-new/test/browser/helper-addons.js",
+      "devtools/client/inspector/animation/animation.js",
+      "devtools/client/inspector/changes/ChangesView.js",
+      "devtools/client/inspector/markup/test/helper_screenshot_node.js",
+      "devtools/client/performance/modules/widgets/graphs.js",
+      "devtools/client/scratchpad/scratchpad.js",
+      "devtools/client/webconsole/webconsole-wrapper.js",
+      "devtools/server/tests/unit/test_breakpoint-17.js",
+      "devtools/shared/adb/adb-process.js",
+      "devtools/shared/fronts/webconsole.js",
+      "dom/l10n/tests/mochitest/document_l10n/non-system-principal/test.html",
+      "dom/payments/test/test_basiccard.html",
+      "dom/payments/test/test_bug1478740.html",
+      "dom/payments/test/test_canMakePayment.html",
+      "dom/payments/test/test_closePayment.html",
+      "dom/payments/test/test_showPayment.html",
+      "dom/tests/browser/browser_persist_cookies.js",
+      "dom/tests/browser/browser_persist_mixed_content_image.js",
+      "netwerk/test/unit/test_http2-proxy.js",
+      "toolkit/components/contentprefs/ContentPrefService2.jsm",
+      "toolkit/components/extensions/ExtensionShortcuts.jsm",
+      "toolkit/components/extensions/ExtensionTestCommon.jsm",
+      "toolkit/components/extensions/test/browser/browser_ext_themes_dynamic_getCurrent.js",
+      "toolkit/components/extensions/test/browser/browser_ext_themes_warnings.js",
+      "toolkit/components/passwordmgr/test/browser/browser_autocomplete_footer.js",
+      "toolkit/components/remotebrowserutils/tests/browser/browser_httpResponseProcessSelection.js",
+      "toolkit/components/satchel/FormHistory.jsm",
+      "toolkit/content/tests/browser/browser_findbar.js",
+      "toolkit/modules/NewTabUtils.jsm",
+      "toolkit/mozapps/extensions/test/browser/browser_CTP_plugins.js",
+      "toolkit/mozapps/extensions/test/browser/head.js",
+    ],
+    "rules": {
+      "no-async-promise-executor": "off",
+    }
   }]
 };

browser/base/content/browser.js

@@ -3402,6 +3402,7 @@ function losslessDecodeURI(aURI) {
   // This includes all bidirectional formatting characters.
   // (RFC 3987 sections 3.2 and 4.1 paragraph 6)
   value = value.replace(
+    // eslint-disable-next-line no-misleading-character-class
     /[\u00ad\u034f\u061c\u115f-\u1160\u17b4-\u17b5\u180b-\u180d\u200b\u200e-\u200f\u202a-\u202e\u2060-\u206f\u3164\ufe00-\ufe0f\ufeff\uffa0\ufff0-\ufff8]|\ud834[\udd73-\udd7a]|[\udb40-\udb43][\udc00-\udfff]/g,
     encodeURIComponent
   );

devtools/client/accessibility/components/AccessibilityPrefs.js

@@ -3,8 +3,6 @@
  * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
 "use strict";
 
-/* global gTelemetry */
-
 // React
 const {
   createFactory,