Make the pretty-printer output whitespace before obj drop clause

Author: marijnh

src/comp/syntax/print/pprust.rs

@@ -507,7 +507,11 @@ fn print_item(s: &ps, item: &@ast::item) {
             print_block(s, meth.node.meth.body);
         }
         alt _obj.dtor {
-          some(dtor) { head(s, "drop"); print_block(s, dtor.node.meth.body); }
+          some(dtor) {
+            space(s.s);
+            head(s, "drop");
+            print_block(s, dtor.node.meth.body);
+          }
           _ { }
         }
         bclose(s, item.span);