[web/data] Fix userCallbackThenUpdateUI to completely replace old DOM elements
Without the 'swap' parameter, userCallbackThenUpdateUI() would replace
the _children_ of the component with a new version of the componenent,
thus creating nested divs/spans/buttons/etc.
Closes #4881299
.. role:: raw-html(raw)
:format: html
RSS driven
----------
RSS is a pretty useful technology that can be widely used on this
site. Any set of data can be presented as RSS. You can then plug in
an RSS reader into that and follow the site activity. For example :
:raw-html:`<p><a class="reference"
href="view?vid=rss&rql=Any+X%2CM+WHERE+X+modification_date+M+ORDERBY+M+DESC+LIMIT+30"><img
alt="rss" src="data/rss.png"> latest changes</a></p>`