Replace signed wordlist by "dash-escaped" one.

In signed files, words with a starting dash are treated special
(they are "dash-escaped" as RFC 4880 says).

tests/sample_signed_wordlist.asc

@@ -3,12 +3,14 @@ Hash: SHA512
 
 foo
 bar
+- -dashat-start
+baz
 -----BEGIN PGP SIGNATURE-----
 Version: GnuPG v1
 
-iJwEAQEKAAYFAlWwtFAACgkQ+5ktCoLaPzT6dAP/YOac16xtJ0oDtVmouhYgXY6J
-A6jyR8nW2tn+5NksBrXgy/OLgwD2ljlZuhPDarancD8e2tkoPKr0Diuk4oTSe4m7
-sAH4PvMPvUw9Rn0gfx20QMbTrLqQ8I4I7cw6u3RIqilB+p80V+SWFApvoHC6l0ZU
-EkreblTdKgoQ2CzP0RM=
-=3BRe
+iJwEAQEKAAYFAlWwxjIACgkQ+5ktCoLaPzRH1gQAlqIeyQj3GGSYHhxwrzewjTus
+2Afh3p/OlEgEq2cd6mMFNw/2Iba3e1ddo2OOHWwg7UqNQrqSwnqEFAgK+HsxY5hD
+KrYDd3e3XnYLMawr6EjI+cqdNbf/e05fdU7jS7CorvE6XoMZLRsLNwV9Oc6R4H40
+0oXXBsnGXLTkFgB/tmk=
+=d6/Q
 -----END PGP SIGNATURE-----