Tristan made a good point, part of the doc building process performs a resolving check and circular reference check, which is ignored by the returned errors. So resolving errors are now unpacked into standard errors and returned. Not sure why gofmt has shifted everything around however.
When paths are wrapped in an array, the index throws an error because it's expecting them to be supplied as a map. Now paths can be wrapped or unwrapped, the index won't care.
This simple method gives the low API a super powerful and simple way to mutate the value of any node, which is then reflected in the root node, can than be serialized again and, voila! now our spec is editable.
