[#2786] addressed comments

src/share/database/scripts/mysql/upgrade_009.5_to_009.6.sh.in

@@ -58,11 +58,13 @@ EOF
 fi
 
 mysql "${@}" <<EOF
+-- This line starts the schema upgrade to version 9.6.
+
 # Add an auto-increment ID as primary key to support Percona.
 ALTER TABLE logs
     ADD id INT UNSIGNED NOT NULL AUTO_INCREMENT PRIMARY KEY;
 
-# Update the schema version number
+# Update the schema version number.
 UPDATE schema_version
     SET version = '9', minor = '6';