Remove all commas before newlines

When 2 hallways are connected by nodes that were each on the RIGHT or LEFT sides of their corresponding hallways (i.e. the connected hallways are parallel), room-finder previously gave directions like this:

Turn right out of room A
Continue, then turn left into hallway 2
, and then turn right
Continue, then turn left into hallway 3
, and then turn left
Continue, then turn right into room F

Now, the newlines before the commas are removed:

Turn right out of room A
Continue, then turn left into hallway 2, and then turn right
Continue, then turn left into hallway 3, and then turn left
Continue, then turn right into room F