[INTERNAL] sap.m.NavContainer: Improved events documentation
[INTERNAL] sap.m.NavContainer: Improved events documentation

Change-Id: I3bf150254d621fc21dcc64176a800586cfba65fd
JIRA: BGSOFUIPIRIN-3634

SAP/openui5,SAP/openui5,SAP/openui5,SAP/openui5