Better command line documentation for signing and verifying: what does --clearsign do?

The [command line usage](https://keybase.io/docs/command_line) page says adding `--clearsign` means "# sign, but don't encode contents". But if I don't use `--clearsign`, I don't get the signed message. Is that correct? This may be a lack of understanding on my part, but I probably won't be last to misunderstand.

So, is this correct?
- with `--clearsign`, it gives you the guarded plain text and then only the guarded signature
- without, it gives you a guarded signature that contains the message in the signature?

$ echo "Space, the final frontier..." | keybase sign --clearsign

You need a passphrase to unlock the secret key for
user: "keybase.io/harvey harvey@keybase.io"
2048-bit RSA key, ID 83366848, created 2013-09-06 (main key ID 000BBDD7)

-----BEGIN PGP SIGNED MESSAGE-----
Hash: SHA512

Space, the final frontier...
-----BEGIN PGP SIGNATURE-----
Version: GnuPG/MacGPG2 v2.0.22 (Darwin)
Comment: GPGTools - https://gpgtools.org

iQEcBAEBCgAGBQJUTECLAAoJEJECmdmDNmhIhPoIAITyfguEeoz8pZ1D4G/MgRM/
r2SGDu+sFqX2+Ac/lZohFDsd6pjc7dc35JkY677+55VfM8EYvQnoUEYve1uGkkyt
yMxsP+ef/9OAcztpKEWs7kopAvWhvcVCpbPB61XpwmxN0IvrzqSGu+p5qpFMviiD
A9EoGqxTLwn0qB43tFQDM6W/slctCy0iFW+DVC3pxWxZL9U3oTx/CmQoBsSf9OU0
lzVXF94AXYIUGWR82PewCS+ig5fVwt5VPOj4vCmB86fWQs/894qGtrPTNZp2QY6m
/ll0ewbFXp2tEZetOI8IaDuktyjXwAX4CgJCrXYUYhKoNkz+l+lV1Wyd8lA5UsY=
=3qr2
-----END PGP SIGNATURE-----

silver:Desktop hchapman$ echo "Space, the final frontier..." | keybase sign

You need a passphrase to unlock the secret key for
user: "keybase.io/harvey harvey@keybase.io"
2048-bit RSA key, ID 83366848, created 2013-09-06 (main key ID 000BBDD7)

-----BEGIN PGP MESSAGE-----
Version: GnuPG/MacGPG2 v2.0.22 (Darwin)
Comment: GPGTools - https://gpgtools.org

owEBUwGs/pANAwAKAZECmdmDNmhIAcsjYgBUTEDBU3BhY2UsIHRoZSBmaW5hbCBm
cm9udGllci4uLgqJARwEAAEKAAYFAlRMQMEACgkQkQKZ2YM2aEijjQgAiFuKr0x2
ejBlgtlP7F8/YM6nT6KG8n8jYAJ+8L/47dLSqUMeSXiC+C32NDIfxDN6ogzX3561
c63pIZQXkjEGXggRehhLvHR2cWNZ0OgocvZmp4/rQrphK9IfH3HigpATKm49TZDn
MbKkxjh0xEHQb4/x5nPyk9Fy8mR+GDB6veYDpPxZfY5D7/YUIEzlp0xCxIUkOTpT
miSlU/v6A5uBAtcyy9vfZYH6PlO38NtZP05fS6TVGmXkck7yQFNCCmhCKXI+3nmf
t95kq87S1awzDehW16w1bOuGui9CacO+H/73OgrhEkNOhTP+vrNrxJjCr9Fjumq0
aJO56S1sxfjnlg==
=nsDb
-----END PGP MESSAGE-----

Start with the linked command line usage page and the documented `keybase sign` and `--clearsign` examples in the issue. Compare the descriptions with the two shown command outputs, then update the documentation so the distinction between clear-signed and encoded signed messages is unambiguous.

Written by the indexing model from the issue text.