Enhance cider-connect to show all nREPLs available ports, instead of only Leiningen ones

[vemv]

Fixes #3390

Rehash of #3392 with some improvements directly applied, while preserving attribution:

• Do more processing in Elisp (vs awk)
• For each 'stragegy' (lein processes, non-lein-process, local, etc), a list of <dir, port> pairs is returned, instead of just dir
  • this avoids redundantly re-computing the ports later.
• avoid permission errors, e.g. trying to read .nrepl-port on macOS /Users/$USER/Desktop

And a minor CI improvement expressed in a separate commit.

I've QA'd all code paths - it works as intended:

Cheers - V

[vemv]

@ag91 feel free to try this one locally.

curl https://patch-diff.githubusercontent.com/raw/clojure-emacs/cider/pull/3399.diff | git apply (over master) may be handy

[ag91]

I was thinking to tackle this with with-demoted-errors (although also ignore-errors would do here if you don't want to let the user know about what caused the ignored error): maybe it saves some code?

[vemv]

Thanks! Sounds reasonable.

Now that I think it, we may want to catch errors for each individual directory entry, instead of for the whole call, so that one bad dir doesn't cause all its neighbors to be excluded.

[bbatsov]

We don't expect duplicates here?

[vemv]

We don't expect duplicates here?

They're handled in the cider--running-nrepl-paths callsite. Which seems better since cider-locate-running-nrepl-ports can cons an element to it, so you'd have to run seq-uniq again