Fix typos in docs (#2011)

Author: michaelgrund

examples/projections/README.txt

@@ -1,9 +1,9 @@
 Projections
 ===========
 
-PyGMT support many map projections. Use the ``projection`` parameter to specify which
-one you want to use in all plotting methods. The projection is specified by a one
-letter code along with (sometimes optional) reference longitude and latitude and the
+PyGMT supports many map projections. Use the ``projection`` parameter to specify which
+one you want to use in all plotting methods. The projection is specified by a one-letter 
+code along with (sometimes optional) reference longitude and latitude and the
 width of the map (for example, **A**\ *lon0/lat0*\ [*/horizon*\ ]\ */width*). The map
 height is determined based on the region and projection.