YAML parsing now working in playground

[char0n]

> Cannot read property 'children' of undefined
   TypeError: Cannot read property 'children' of undefined
    at isValuelessKeyValuePair (http://localhost:3000/static/js/main.chunk.js:4833:133)
    at Object.enter (http://localhost:3000/static/js/main.chunk.js:5009:13)
    at visit (http://localhost:3000/static/js/main.chunk.js:5573:26)
    at transform (http://localhost:3000/static/js/main.chunk.js:5190:73)
    at _callee$ (http://localhost:3000/static/js/main.chunk.js:48213:96)
    at tryCatch (http://localhost:3000/static/js/0.chunk.js:65799:17)
    at Generator.invoke [as _invoke] (http://localhost:3000/static/js/0.chunk.js:66019:22)
    at Generator.prototype.<computed> [as next] (http://localhost:3000/static/js/0.chunk.js:65852:21)
    at asyncGeneratorStep (http://localhost:3000/static/js/0.chunk.js:3936:24)
    at _next (http://localhost:3000/static/js/0.chunk.js:3958:9)
> Cannot read property 'children' of undefined
   TypeError: Cannot read property 'children' of undefined
    at isValuelessKeyValuePair (http://localhost:3000/static/js/main.chunk.js:4833:133)
    at Object.enter (http://localhost:3000/static/js/main.chunk.js:5009:13)
    at visit (http://localhost:3000/static/js/main.chunk.js:5573:26)
    at transform (http://localhost:3000/static/js/main.chunk.js:5190:73)
    at _callee$ (http://localhost:3000/static/js/main.chunk.js:48213:96)
    at tryCatch (http://localhost:3000/static/js/0.chunk.js:65799:17)
    at Generator.invoke [as _invoke] (http://localhost:3000/static/js/0.chunk.js:66019:22)
    at Generator.prototype.<computed> [as next] (http://localhost:3000/static/js/0.chunk.js:65852:21)
    at asyncGeneratorStep (http://localhost:3000/static/js/0.chunk.js:3936:24)
    at _next (http://localhost:3000/static/js/0.chunk.js:3958:9)

[char0n]

there seems to be inconsistencies between node.js tree-sitter and web-tree-sitter CST

[char0n]

Linked issue about latest web-tree-sitter not working: tree-sitter/tree-sitter#873

[char0n]

Linked issue about web-tree-sitter not interpreting "FIELDS" to resulting Tree: tree-sitter/tree-sitter#874