QtWebKit documentation regression fixes
Summary:
Make QtWebKit documentation view work again
Since commit 2486228ccee2280af10f8e202d8020abe89880fc
setUpdatesEnabled(true) was called on QWidget instead of QWebView.
This prevented QWebView contents updates and rendered
documentation plugins useless.
Use delegate parameter in QtWebKit documentation
Test Plan: manual testing
Reviewers: kfunk, apol
Reviewed By: kfunk
Subscribers: kdevelop-devel
Differential Revision: https://phabricator.kde.org/D5129