Need rendering for dated placename variants

[martindholmes]

There is a small number of places which have multiple place elements at the top of their body, where each is a variant place name; some of these have date ranges.

We're currently not processing that information at all, but we should catch these cases and output onto the location page something like:

Also known as:

• The Thing (1555-1590)
• The Other Thing (1591-)

[martindholmes]

Question for @JanelleJenstad and @mrothwell23 : These are not variant names or spellings, so they presumably shouldn't go in the list of those; instead, these are alternative canonical forms of the name, so they should appear somewhere else. The main canonical name of the place appears in the h1 heading tag at the head of the content area of the web page; should we add these alternative canonical forms directly below it?