Day 19 walkthrough explanation is different than rule

[Steve Nicholson]

In the walkthrough for Day 19, the example rule 0 is 1 2 | 2 3. But in the second paragraph after the example, it starts treating it as 1 2 | 1 3:

this second option of rule 0 means "match a followed by b followed by a"

This should be "match b followed by b followed by a"

Also, the tree shows 1 2 | 1 3.

[Marco Bonelli]

Thank you for spotting this! Fixed in a6cc226.