Change "Not supported" to "N/A" for Safari on Windows

[Studio384]

In desktop browsers, Safari is noted as "Not supported", but as its latest release is from 2011 (Safar 5.1), shouldn't that be changed to "N/A", a 4 year gap is more than enough to consider the browser unexisting on Windows. IE for Mac is also not noted as "Not supported".

[cvrebert]

You would be surprised. People have actually filed Bootstrap bug reports regarding Windows Safari, with no shame in several cases, presumably due to lack of knowledge.
I would prefer to keep the existing "Not supported" labelling to make it perfectly unambiguous that we don't support it.

[patrickhlauke]

/me fires up IE5.5/Mac to file some bugs ;)

[mdo]

Leaving as is for now.

[cvrebert]

Gratuitous examples:
#16377, #15349 (comment), #11189, #13117 (comment), #11028, #10829 (comment)