Bug 34385: Correct page heading of transport cost matrix page

Bug 34385: Correct page heading of transport cost matrix page

This patch corrects the main heading on the transport cost matrix page
so that it matches the page title and breadcrumb navigation.

To test, apply the patch and go to Administration -> Transport cost
matrix. Confirm that the page heading reads "Transport cost matrix."

Signed-off-by: Lucas Gass <lucas@bywatersolutions.com>
Signed-off-by: Tomas Cohen Arazi <tomascohen@theke.io>
(cherry picked from commit c7daaa901b6ec8a0fa6e2b0a8ffb7f9e6befbc5e)
Signed-off-by: Fridolin Somers <fridolin.somers@biblibre.com>