Javadoc: Use "latitude/longitude" instead of "latitude,longitude" everywhere

[apjanke]

In this project, when talking about latitude/longitude coordinates, the styling "latitude/longitude" is predominant over "latitude,longitude". (And IMHO, "latitude/longitude" is more conventional English prose.)

$ grep -r latitude/longitude * | wc -l
      22
$ grep -r latitude,longitude * | wc -l
       2

This PR changes the remaining "latitude,longitude" instances to be "latitude/longitude".

It also removes the {@code ...} markup from one of the instances, because it's not referring to a literal code value or identifiers there.

[domesticmouse]

Thanks!