Have you heard of NestedText? YAML-like, simpler, unambiguous, readable.
I myself made an (experimental) implementation of NestedText v1 (minus
the quoted keys feature) in Go without too much trouble.
I should note that the author of the spec recently made breaking changes
to the format which I feel deviated from the core simplicity NestedText
Therefore, NestedText v1 is near-perfect, but suffers from some
bloat-creep I want to flesh out in a new format based on it. Should
anyone be interested in discussing this, email me.