[INTERNAL] sap.ui.model.odata.v4.Context#setKeepAlive: adjust API documentation
[INTERNAL] sap.ui.model.odata.v4.Context#setKeepAlive: adjust API documentation

PS1: init
PS2: review comments

Change-Id: Iddca2c9301deb9a99561f4376c588d232a1435d4
JIRA: CPOUI5ODATAV4-1614

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