updated docs: initialPage to page
updated docs: initialPage to page

VadimDez/ng2-pdf-viewer,2020-vision/ttv-ng2-pdf-viewer,VadimDez/ng2-pdf-viewer,VadimDez/ng2-pdf-viewer,2020-vision/ttv-ng2-pdf-viewer,2020-vision/ttv-ng2-pdf-viewer