Make RAI Institute... a research institute (#258)

I had missed that there was a category for this until I viewed the map. Sorry.

Author: sea-bass

data/america.yaml

@@ -421,7 +421,7 @@
   address: 2500, chemin de Polytechnique, Montreal (Quebec) H3T 1J4 Canada
   link: https://www.polymtl.ca/
 - name: Robotics and AI Institute
-  type: company
+  type: research institute
   lat: 42.364931
   long: -71.088803
   address: 145 Broadway, Cambridge, MA 02142