remove space in page revisions title

closes #CNVS-14351

Change-Id: Id4e04b90577b1651ba4d3bab9546b3743b38499a
Reviewed-on: https://gerrit.instructure.com/37936
Tested-by: Jenkins <jenkins@instructure.com>
Reviewed-by: Jeremy Stanley <jeremy@instructure.com>
Product-Review: Jeremy Stanley <jeremy@instructure.com>
QA-Review: James Williams  <jamesw@instructure.com>