convert to sentence

goblins/scribblings/api.scrbl

@@ -79,7 +79,7 @@ Goblins' extensions to these ideas are:
           to move from a coroutine-centric approach to an
           @link["http://www.erights.org/"]{E}-style promise approach.
           It could be that coroutines are re-added, but would have to be done
-          with extreme care; section 18.2 of that same thesis for an
+          with extreme care. Section 18.2 of that same thesis for an
           explanation of the challenges and a possible solution for
           introducing coroutines.}}
   @item{Raw message passing without a clear way to get values back can