More tests of doc comments and attributes.

Author: cristianoc

tests/printer/comments/docComments.res

@@ -20,4 +20,10 @@ type h = int
 @foo let x = 10
 
 /** doc comment and attribute */
-@foo let x = 10
+@foo let x = 10
+
+/** doc comment and 3 attributes */
+@foo @bar @baz let x = 10
+
+/** doc comment and 0 attributes */
+let x = 10

tests/printer/comments/expected/docComments.res.txt

@@ -22,3 +22,12 @@ type h = int
 /** doc comment and attribute */
 @foo
 let x = 10
+
+/** doc comment and 3 attributes */
+@foo
+@bar
+@baz
+let x = 10
+
+/** doc comment and 0 attributes */
+let x = 10