Symbol Construction pages do not include examples of truetype symbol fills for polygons

[arthur-clifford]

I recently asked the user mailing list if it was possible to use a truetype symbol as a fill. Someone confirmed it was possible.

Currently the Cartographic Symbol Construction page regarding Area Symbols erroneously implies that only pxmap, vector, and hashes are possible as fill patterns by providing no other examples or mentions of other symbol types.

At the very least it should be confirmed that any type of point symbol (non hashes or ranges) should be viable as polygon fills and whichever point symbol types are valid should be mentioned with examples in the Cartogaphic Symbol Construction Area Fills section:

https://www.mapserver.org/mapfile/symbology/construction.html#area-symbols

[jmckenna]

@arthur-clifford it would be great if you could create a pull request for this change. Regarding 'confirming', indeed this is part of my documentation steps for such requests, to test it first, so please do test this and then create a pull request. thanks!