Multilang tags appear in activity completion tips

When using the multilang filter (http://docs.moodle.org/en/Multi-language_content_filter) with activity completion, the span tags used in activity names are present in the tip that appears when hovering over an activity completion checkbox.

Replication steps:

1. Log in as admin
2. Navigate to Site admin > Plugins > Filters > Manage filters
3. Set the Multi-language content filter to On and allow it to apply to "Content and headings"
4. Navigate to Site admin > Advanced features
5. Check "Enable completion tracking" (enablecompletion)
6. Navigate to a course
7. Edit the course's settings and in the Student progress section, set Completion tracking to "Enabled,..."
8. Save settings
9. Turn editing on
10. Create an activity such as a quiz.
11. Add the following as the activity name: <span lang="en" class="multilang">This is a test</span><span lang="de" class="multilang">Dies ist ein Test</span>
12. In the Activity completion settings section, set the Completion tracking option to "Students can manually mark..."
13. Save the activity and return to the course
14. Turn editing off
15. Hover over the completion checkbox for the newly created quiz

Expected result: The tip shows "Mark as complete:" followed by the filtered name

Actual result: The name supplied with tags and both translations appears