pg_dumpall examples may lead to encoding problems

The following documentation comment has been logged on the website:

Page: https://www.postgresql.org/docs/10/static/app-pg-dumpall.html
Description:

The example to dumb all databases at the bottom of the page "pg_dumpall >
db.out" works, but I think it would be better to suggest "pg_dumpall -f
db.out" instead, as it uses the database's encoding for the db.out file.
Using the current example on Windows led to the db.out file being in the
wrong encoding and not working to restore the database.