Workaround haddock parser error caused by 5e7406d9

Haddock complains if a comment looks like a misplaced Haddock-comment.
In this case, the comment line starting with `-- *kind* and` looked like a
section-heading to Haddock and caused the following error:

    parse error on input ‘-- *kind* and role of its argument. Luckily, laziness should’

This commit just rewraps the line so that no `*` appear at the start of the
non-Haddock comment lines.

Signed-off-by: Herbert Valerio Riedel <hvr@gnu.org>