Removed unneeded newlines from parsed comments

Newlines from comments separated by lines are retained when comments
are appended, so adding a newline between separate comments for a
node is not needed.

test/data/test_comment_02.json

@@ -9,7 +9,8 @@
    },
    // C++-style comment
    "cpp-test" : {
-      // Internal comment cpp-style
+      // Multiline comment cpp-style
+      // Second line
       "c" : 3,
       "d" : 4
    }