session: improve .api comments slightly
session: improve .api comments slightly

Type: style

Change-Id: Iccd2c205059abcdf121093ff03da603fe3dda1f7
Signed-off-by: Vratko Polak <84c5f374c860783d46e9bccfb1dae3a5cc35d4f7@cisco.com>

FDio/vpp,FDio/vpp,FDio/vpp,chrisy/vpp,FDio/vpp,chrisy/vpp,chrisy/vpp,chrisy/vpp,chrisy/vpp,chrisy/vpp,FDio/vpp,FDio/vpp,chrisy/vpp,chrisy/vpp,FDio/vpp,FDio/vpp