update: 'map data' guide page updated with added info about new "2D" schematic map & fixes

[SentientTurtle]

Updated 'Map Data' guide page:

• Added some information about the new 'Postion2D' schematic map data, including image for the coordinate system
• Rephrased previous text that used the word "2D", to disambiguate from the new 'Postion2D' data
• Example snippet modified to load data from the SDE & updated with additional comments explain the rendering calculations and tie the explanation above the snippet to which parts of the line of code do what
  • Example snippet filename changed from 'map-2d-cluster' to 'map-cluster' to disambiguate

The new '2D' map data is referred to as a 'schematic' map in these changes, this is clearer than the jargon of 'topological map' but the phrasing changes could use another set of eyes to make sure it makes sense to someone not familiar with the subject.