`chain-spec-builder`: Improve output path example (#2693)
Example currently broken.
It writes something to the given path, but not the full chain spec.
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Co-authored-by: 
Michal Kucharczyk <[email protected]>
Example currently broken.
It writes something to the given path, but not the full chain spec.
---------
Co-authored-by: Michal Kucharczyk <[email protected]>