fix: property Discovers() in client.go

[jnweiger]

Storing json Decode() results in the client c object does not seem right. It probably silently ignores everything.

There is an unused var cap Capabilities directly above, that is returned uninitialized directly below. I assume it was meant to use this variable cap instead of the variable c.

[update-docs[bot]]

Thanks for opening this pull request! The maintainers of this repository would appreciate it if you would create a changelog item based on your changes.