A fork of tree-sitter-yaml looks necessary

[cscheid]

https://github.com/ikatyang/tree-sitter-yaml looks to be unmaintained (last commit was 18 months ago)

Unfortunately, it parses YAML incorrectly: ikatyang/tree-sitter-yaml#29

This is also coming from tree-sitter: #2498

We don't have in-house tree-sitter expertise to take over that code base atm, but it feels like we will have to.