Mark DataTransferItem supported in Safari 5.1 (#6071)
Mark DataTransferItem supported in Safari 5.1 (#6071)

https://trac.webkit.org/changeset/80536/webkit added `DataTransferItem`
support to WebKit. Per https://trac.webkit.org/log/webkit/tags/Safari-534.24
that puts it in WebKit 534.24, which means it shipped in Safari 5.1.
mdn/browser-compat-data,chrisdavidmills/browser-compat-data,chrisdavidmills/browser-compat-data,mdn/browser-compat-data