[doc fix] PG10: wroing description on connect_timeout when multiple hosts are specified

Hello, Robert

I found a wrong sentence here in the doc. I'm sorry, this is what I asked you to add...

https://www.postgresql.org/docs/devel/static/libpq-connect.html#libpq-paramkeywords

connect_timeout
Maximum wait for connection, in seconds (write as a decimal integer string). Zero or not specified means wait indefinitely. It is not recommended to use a timeout of less than 2 seconds. This timeout applies separately to each connection attempt. For example, if you specify two hosts and both of them are unreachable, and connect_timeout is 5, the total time spent waiting for a connection might be up to 10 seconds.

The program behavior is that libpq times out after connect_timeout seconds regardless of how many hosts are specified. I confirmed it like this:

$ export PGOPTIONS="-c post_auth_delay=30"
$ psql -d "dbname=postgres connect_timeout=5" -h localhost,localhost -p 5432,5433
(psql erros out after 5 seconds)

Could you fix the doc with something like this?

"This timeout applies across all the connection attempts. For example, if you specify two hosts and both of them are unreachable, and connect_timeout is 5, the total time spent waiting for a connection is up to 5 seconds."

Should we also change the minimum "2 seconds" part to be longer, according to the number of hosts?

Regards
Takayuki Tsunakawa