More permissive orchard.info parsing of stacktrace output

[alexander-yakushev]

This is part 1 of simplifying Haystack usecases. I think this PR is self-sufficient enough to be reviewed individually.

The proposed changes relax the requirements for Java classes/members and Clojure vars to be inferred using orchard.info/info. Now it can recognize all printed stacktrace formats. The examples are in the tests. This influences:

• Better jump to definition (can jump directly from the REPL output without no extra prep)
• Better cider-doc support
• Even eldoc (this looks a bit funny, consider yourself if we should restrict this somehow).

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• You've added tests to cover your change(s)
• You've updated the changelog

[bbatsov]

The proposed changes look very good to me!

I'd say the eldoc in the stacktraces is a feature.