improve description of command x-add-key

if keys are send as attachment, they can also be in binary format

schleuder/docs/list-admins.md

@@ -32,8 +32,8 @@ These keywords must be send to `foo-request@hostname`. They are used to get info
 **x-list-keys**
 : Lists all public keys known to the list. To see only keys that match a given string, use `x-list-keys: something`.
 
-**x-add-key:**
-: Import the attachments or the rest of the email-body into the list's keyring. Only ascii-armored keys are supported.
+**x-add-key:**  
+: Import the request-mails attachment(s) or the rest of the email-body into the list’s keyring. To paste your public key into the body of the request-mail, please export it in _"ASCII-armored"_ text format (e.g. `gpg --armor --export 0xAE0DBF5A92A5ADE49481AB6F8A3171EF366150CE`). If you send the key as an **attachement** of the request-mail, **both** _"ASCII-armored"_ and binary format are supported. 
 
 **x-delete-key:** 0x12345678DEADBEEF12345678DEADBEEF12345678
 : Delete the key with the given fingerprint from the list's keyring.

schleuder/docs/subscribers.md

@@ -15,7 +15,8 @@ The following keywords must be send to the request address of the list: `foo-req
 Include `x-list-name: foo@hostname` with every command you send.
 
 **x-add-key:**  
-: Import the attachment(s) or the rest of the email-body into the list’s keyring. Only ascii-armored keys are supported.
+: Import the request-mails attachment(s) or the rest of the email-body into the list’s keyring. To paste your public key into the body of the request-mail, please export it in _"ASCII-armored"_ text format (e.g. `gpg --armor --export 0xAE0DBF5A92A5ADE49481AB6F8A3171EF366150CE`). If you send the key as an **attachement** of the request-mail, **both** _"ASCII-armored"_ and binary format are supported. 
+
 
 **x-set-fingerprint:** 0x12345678DEADBEEF12345678DEADBEEF12345678
 : Assign the key with the given fingerprint to your subscription. It is not possible to set an empty fingerprint. To unset your fingerprint use `x-unset-fingerprint`.