Move oauth_validator_libraries in postgresql.conf.sample

Move oauth_validator_libraries in postgresql.conf.sample to be grouped
with the other CONN_AUTH_AUTH settings, rather than making up a new
ad-hoc category.  This matches the internal categorization and also
how it is listed in the documentation.

Author: petere

src/backend/utils/misc/postgresql.conf.sample

@@ -97,6 +97,7 @@
 #password_encryption = scram-sha-256	# scram-sha-256 or md5
 #scram_iterations = 4096
 #md5_password_warnings = on
+#oauth_validator_libraries = ''	# comma-separated list of trusted validator modules
 
 # GSSAPI using Kerberos
 #krb_server_keyfile = 'FILE:${sysconfdir}/krb5.keytab'
@@ -121,9 +122,6 @@
 #ssl_passphrase_command = ''
 #ssl_passphrase_command_supports_reload = off
 
-# OAuth
-#oauth_validator_libraries = ''	# comma-separated list of trusted validator modules
-
 
 #------------------------------------------------------------------------------
 # RESOURCE USAGE (except WAL)