Auto-linking not working if title has brackets

Step-by-step instructions:

1. Go to a course and turn editing on
2. Create a file resource named "Test 1"
3. Create a file resource named "Test (2)"
4. Add a new activity e.g Label with following content: "Please read Test 1 and Test (2)"
5. Check the result

Expected result:

• The label should link to the two file resources.

Actual result:

• The auto-linking works only to the resource without brackets in the title.

Additional information:

The filter/glossary had only one change (https://github.com/moodle/moodle/commits/MOODLE_35_STABLE/filter/glossary) in the recent time.

In due of that, I think it's a regression of MDL-63403.

I can confirm that with Moodle 3.5.2+ (Build: 20181005) it was working like the expected result.