[cleanup] Remove "Update flavors" from documentation
[cleanup] Remove "Update flavors" from documentation

"Edit Flavor" feature is dropped in horizon by 377422b
and this patch removes its reference from the documentation
to avoid confusion.

Closes-Bug: #1940035
Change-Id: I76a0e0052c7ede9f9e9751b39a6264ffeb0322e3

openstack/horizon,openstack/horizon,openstack/horizon,openstack/horizon