[bug-mailutils] date format and documentation

[積丹尼 Dan Jacobson]

On (info "(mailutils) Mail Variables")

Letter Meaning
--------------------------------------------------------------------------
%a Message attributes.
%d The date when the message was received. **mention *Note datefield:: here too**
%f The address of the message sender.
%l The number of lines of the message.
%m Message number.
%o The number of octets (bytes) in the message.

Also here you should also have date(1) % modifiers, as one would
probably not want a one size fits all date style!

[積丹尼 Dan Jacobson]

On (info "(mailutils) Mail Variables")

%f The address of the message sender.

Address? My tests show it is printing the name, not address.

Therefore say

%f The name of the message sender.

And if you have spare time implement another % to show the address.