Correct description of insertion cloning behavior

[jugglinmike]

When an element is to be inserted in multiple locations in the DOM, all
four of these manipulation methods behave in the same way: they insert a
clone for all but the last matched location.

From jQuery's implementation of the internal domManip method [1]:

Use the original fragment for the last item instead of the first
because it can end up being emptied incorrectly in certain situations
(#8070).

[1]
https://github.com/jquery/jquery/blob/988d99ad278c2c9dc16c68f86bddc4df99dcd928/src/manipulation.js#L506-L522