Update Wiki API docs to help users with brackets in API calls

Test Plan
- Wiki Page API docs should now show any params with brackets after a newline and -d

Change-Id: Iebd7fbb9d7d3dac5cfab0b7cc075d7c4330b8f62
Reviewed-on: https://gerrit.instructure.com/34203
Tested-by: Jenkins <jenkins@instructure.com>
Reviewed-by: Jeremy Stanley <jeremy@instructure.com>
Product-Review: Jeremy Stanley <jeremy@instructure.com>
QA-Review: Clare Strong <clare@instructure.com>