Fix formatting of trailing comments.

If a trailing comment is on a line with disabled formatting, then it should be
placed in the original column after the formatting.
diff --git a/CHANGELOG b/CHANGELOG
index ab62a36..1fec408 100644
--- a/CHANGELOG
+++ b/CHANGELOG
@@ -10,6 +10,7 @@
 
 ### Fixed
 - Lessen penalty for splitting before a dictionary keyword.
+- Formatting of trailing comments on disabled formatting lines.
 
 ## [0.6.3] 2016-03-06
 ### Changed