Add note to README

Signed-off-by: Ian Lewis <ianmlewis@gmail.com>

README.md

@@ -93,6 +93,7 @@ In order for the comments to be more easily parsed keep in mind the following:
 - TODOs should have a colon if a message is present so it can be distingished
   from normal comments.
 - Comments can be on the same line with other code (e.g. `x = f() // TODO: call f`
+- Line comment start sequences can be repeated (e.g. `//// TODO: some comment`)
 - Only the single line where the TODO occurs is printed for multi-line comments.
 - `TODO`,`FIXME`,`BUG`,`HACK`,`XXX`,`COMBAK` are supported by default. You can
   change this with the `--todo-types` flag.