More typos and suggestions

[Michael <mike.d.ft402%gmail.com@localhost>]

Hello,

I would like to tell you about some bugs I've recently encountered, along with 
ideas of possible enhancement.

The NetBSD Guide, 27.1.1 Configuration of generic mapping
        smtp_generic_maps = hash:/etc/postfix/generic
The variable does not exist anymore. After a long time spent searching the web, 
I found out it has been renamed to "sender_canonical_maps", and either it's not 
mentioned in the manpages, or I simply overlooked it.

It would be nice to see some more examples, like this one, that allows the use 
of gmail, who require authentication and encryption:
        smtp_use_tls = yes
        smtp_sasl_auth_enable = yes
        relayhost = [smtp.gmail.com]:587
        smtp_sasl_password_maps = hash:/etc/postfix/sasl_passwd
        smtp_sasl_security_options =
        sender_canonical_maps = hash:/etc/postfix/generic
        message_size_limit = 20480000
The contents of sasl_passwd are:
        # destination                   credentials
        [smtp.gmail.com]:587            mike.d.ft402:p4$$W0rD
        # [mail.isp.example]:submission username:password
It and sasl_passwd.db must have proper mode (640?) so that random people can 
not see their contents.

The "message_size_limit" variable is very useful on its own, for emails 
nowadays may contain large attachments, and might fail to be delivered locally. 
If you run fetchmail from cron, that might give an illusion of having no 
incoming mail.

Speaking of cron, it would be nice to mention it in "27.2 fetchmail", for this 
saves the trouble of checking mail manually once in a while.

Some minor typos I've found elsewhere:
The NetBSD Guide
        13.10 Using a CD-R writer with data CDs
                s/an pre-existing/a pre-existing/
        27.1.1 Configuration of generic mapping
                s/need change/need to change
The Pkgsrc Guide
        4.2.2. Fetching distfiles
                s/holding/are holding/
        9.15. Why do some packages ignore my CFLAGS?
                s/so bad code/code so badly/

I was not sure where to mail about this, so I decided to put it with the rest:
The message of "cdrtools -atip"
        s/Unformated/Unformatted

Sincerely,
Mike