updated for version 7.3.541
Problem:    When joining lines comment leaders need to be removed manually.
Solution:   Add the 'j' flag to 'formatoptions'. (Lech Lorens)
diff --git a/runtime/doc/change.txt b/runtime/doc/change.txt
index 3e19b1d..597d1db 100644
--- a/runtime/doc/change.txt
+++ b/runtime/doc/change.txt
@@ -1522,6 +1522,12 @@
 	characters.  Overruled by the 'M' flag.
 1	Don't break a line after a one-letter word.  It's broken before it
 	instead (if possible).
+j	Where it makes sense, remove a comment leader when joining lines.  For
+	example, joining:
+		int i;   // the index ~
+		         // in the list ~
+	Becomes:
+		int i;   // the index in the list ~
 
 
 With 't' and 'c' you can specify when Vim performs auto-wrapping: