docs: clarify handling of loglevel (#711)
docs: clarify handling of loglevel (#711)

I added a note that the log is written to the destination set by a
call to java.sql.DriverManager.setLogWriter(PrintWriter).

I also fixed some typos and clarified that class names passed as
connection parameters must be in a format that can be used by
Class.forName(String).
lordnelson/pgjdbc,marschall/pgjdbc,jkutner/pgjdbc,AlexElin/pgjdbc,AlexElin/pgjdbc,whitingjr/pgjdbc,davecramer/pgjdbc,sehrope/pgjdbc,jamesthomp/pgjdbc,sehrope/pgjdbc,jorsol/pgjdbc,zemian/pgjdbc,zapov/pgjdbc,davecramer/pgjdbc,zapov/pgjdbc,whitingjr/pgjdbc,sehrope/pgjdbc,zapov/pgjdbc,zemian/pgjdbc,golovnin/pgjdbc,panchenko/pgjdbc,jorsol/pgjdbc,jorsol/pgjdbc,Gordiychuk/pgjdbc,jorsol/pgjdbc,pgjdbc/pgjdbc,jkutner/pgjdbc,marschall/pgjdbc,golovnin/pgjdbc,pgjdbc/pgjdbc,Gordiychuk/pgjdbc,sehrope/pgjdbc,davecramer/pgjdbc,marschall/pgjdbc,pgjdbc/pgjdbc,pgjdbc/pgjdbc,marschall/pgjdbc,zemian/pgjdbc,lordnelson/pgjdbc,AlexElin/pgjdbc,golovnin/pgjdbc,davecramer/pgjdbc,panchenko/pgjdbc,jkutner/pgjdbc,whitingjr/pgjdbc,Gordiychuk/pgjdbc,lordnelson/pgjdbc,panchenko/pgjdbc,jamesthomp/pgjdbc,jamesthomp/pgjdbc