Demos: Fix typing errors in table-reflow demo

'prsentation', 'descibed', 'Jaunuary', 'Precipitaion'

@arschmitz: Had to close [my prior PR](https://github.com/jquery/jquery-mobile/pull/7616), used the wrong email address (not the one I signed the CLA for). Hope this checks out and my rather substantial contributions can be merged.