New comment by Eluminae on mblaze repository

https://github.com/leahneukirchen/mblaze/issues/202#issuecomment-771573775

Comment:
> mencrypt uses --encrypt --sign so that should be fine.

I'll double check this part so

> I think above error results due to using mverify as a filter, but it's a tool you need to call on the whole message.

oh ? But it seems that the vanilla mverify can't check the signature too

```
[reed@terminator ~]$ mshow
From: sourcehut <outgoing@sr.ht>
Subject: Test email
To: foo@bar.net
Date: Tue, 02 Feb 2021 10:39:28 -0000 (49 minutes, 57 seconds ago)

--- 1: multipart/encrypted size=2246 filter="mgpg" ---
--- --- 2: multipart/signed size=1138 ---
--- --- --- 3: text/plain size=356 ---
This is a test email sent from sourcehut to confirm that PGP is working as you
expect. This email is signed with this key:

447B 69E4 B34B E90B C829 A0E9 6597 04D1 A38A 93AE

and is encrypted with this key:

CAB1 2F60 BD13 A21D AB60  C510 5BAC 9232 8B7C 5D65

You may control your PGP settings here:

https://meta.sr.ht/privacy

--
Drew DeVault
sourcehut
--- --- --- 4: application/pgp-signature size=455 name="signature.asc" render="mverify; exit 0" ---
No signature found.
[reed@terminator ~]$ mverify
No signature found.
```

The signature seems included in the encrypted part as the raw email looks like 

```
From: sourcehut <outgoing@sr.ht>
Subject: Test email
To: foo@bar
Date: Tue, 02 Feb 2021 10:39:28 -0000 (54 minutes, 34 seconds ago)

--===============5503615174114557129==
Content-Type: application/pgp-encrypted

Version: 1
--===============5503615174114557129==
Content-Type: application/octet-stream; name="message.asc"
Content-Description: OpenPGP encrypted message

-----BEGIN PGP MESSAGE-----
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=gJPx
-----END PGP MESSAGE-----

--===============5503615174114557129==--
```

Anyway I'll adapt it to be usable as filter. I'd like to display signature verification with mless