fixed display of nested arrays on API documentation

arrays found within arguments in documentation are converting to hyperlinks

fixes CNVS-8092

test plan:
- visit the following links
- doc/api/submissions.html#method.submissions_api.update
- should show rubric_assessment[criterion_id][comments]
- doc/api/users.html#method.users.update
- should show user [avatar] [url]
- doc/api/submissions.html#method.submissions.create
- should show submission [submission_type] and submission [url]
- doc/api/assignments.html#method.assignments_api.update
- should show assignment [assignment_overrides]
Change-Id: Ie5eea14821a5fb172e2a8d4ee62a1cc19ab72b60
Reviewed-on: https://gerrit.instructure.com/38392
Reviewed-by: Mike Nomitch <mnomitch@instructure.com>
QA-Review: Amber Taniuchi <amber@instructure.com>
Tested-by: Jenkins <jenkins@instructure.com>
Product-Review: Matt Berns <mberns@instructure.com>