Re: doc: Fix description of how the default user name is chosen

"David G. Johnston" <david.g.johnston@gmail.com> writes:
>     In passing, the authentication error examples use the phrase
>     "database user name" in a couple of locations.  The word
>     database in both cases is both unusual and unnecessary for
>     understanding.  The reference to user name means the one in/for the
>     database unless otherwise specified.

I'm not convinced that just saying "user name" is an improvement.
The thing that we are trying to clarify in much of this section
is the relationship between your operating-system-assigned user
name and your database-cluster-assigned user name.  So just saying
"user name" adds an undesirable element of ambiguity.

Maybe we could change "database user name" to "Postgres user name"?

-    if you do not specify a database name, it defaults to the database
-    user name, which might or might not be the right thing.
+    if the database name shown matches the user name you are connecting
+    as it is not by accident: the default database name is the
+    user name.

This does absolutely not seem like an improvement.

     Since the database server uses the same default, you will not have
     to specify the port in most cases. The default user name is your
-    operating-system user name, as is the default database name.
+    operating-system user name. The default database name is the resolved user name.

I agree this phrasing needs some work, but "resolved" doesn't seem
helpful, since it's not defined here or nearby.  Maybe "The default
database name is the specified (or defaulted) user name." ?