[INTERNAL][FIX]: sap.m.PDFViewer: Improve documentation
[INTERNAL][FIX]: sap.m.PDFViewer: Improve documentation

Change-Id: I9aff90fd1aa2d18c625dc3b51c0d91616a0e9aa5

SAP/openui5,SAP/openui5,nzamani/openui5,SAP/openui5,SQCLabs/openui5,SQCLabs/openui5,SAP/openui5,SQCLabs/openui5,nzamani/openui5,nzamani/openui5,cschuff/openui5,cschuff/openui5,cschuff/openui5