code: replace 'master' with 'primary' where appropriate.
Also changed "in the primary" to "on the primary", and added a few
"the" before "primary".
Author: Andres Freund
Reviewed-By: David Steele
Discussion: https://postgr.es/m/
20200615182235.x7lch5n6kcjq4aue@alap3.anarazel.de