Internationalisation of raven directory

This is one of many MRs opened in order to improve the overall
internationalisation of the GitLab codebase.

i18n documentation
https://docs.gitlab.com/ee/development/i18n/externalization.html

app/assets/javascripts/raven/raven_config.js

 import Raven from 'raven-js';
 import $ from 'jquery';
+import { __ } from '~/locale';
 
 const IGNORE_ERRORS = [
   // Random plugins/extensions
@@ -9,9 +10,9 @@ const IGNORE_ERRORS = [
   'canvas.contentDocument',
   'MyApp_RemoveAllHighlights',
   'http://tt.epicplay.com',
-  "Can't find variable: ZiteReader",
-  'jigsaw is not defined',
-  'ComboSearch is not defined',
+  __("Can't find variable: ZiteReader"),
+  __('jigsaw is not defined'),
+  __('ComboSearch is not defined'),
   'http://loading.retry.widdit.com/',
   'atomicFindClose',
   // Facebook borked
@@ -80,7 +81,7 @@ const RavenConfig = {
 
   handleRavenErrors(event, req, config, err) {
     const error = err || req.statusText;
-    const responseText = req.responseText || 'Unknown response text';
+    const responseText = req.responseText || __('Unknown response text');
 
     Raven.captureMessage(error, {
       extra: {

locale/gitlab.pot

@@ -1593,6 +1593,9 @@ msgstr ""
 msgid "Can't find HEAD commit for this branch"
 msgstr ""
 
+msgid "Can't find variable: ZiteReader"
+msgstr ""
+
 msgid "Cancel"
 msgstr ""
 
@@ -2409,6 +2412,9 @@ msgstr ""
 msgid "Collapse sidebar"
 msgstr ""
 
+msgid "ComboSearch is not defined"
+msgstr ""
+
 msgid "Command line instructions"
 msgstr ""
 
@@ -9952,6 +9958,9 @@ msgstr ""
 msgid "Unknown format"
 msgstr ""
 
+msgid "Unknown response text"
+msgstr ""
+
 msgid "Unlock"
 msgstr ""
 
@@ -11080,6 +11089,9 @@ msgstr ""
 msgid "it is too large"
 msgstr ""
 
+msgid "jigsaw is not defined"
+msgstr ""
+
 msgid "latest"
 msgstr ""