Acknowledge cljs dependency in `tools.deps` docs

[duncanjbrown]

When I followed the instructions to run an nREPL using clj I got a compilation error containing the following message:

java.io.FileNotFoundException: Could not locate clojure/tools/reader__init.class, clojure/tools/reader.clj or clojure/tools/reader.cljc on classpath.

Adding a deps.edn dependency on clojure.tools.reader fixes that, but reveals another dependency error. It eventually becomes clear that Piggieback simply depends on ClojureScript.

Add a note to the README to help the next person.

[codecov-io]

Codecov Report

Merging #104 into master will not change coverage. The diff coverage is n/a.

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  Lines         190      190           
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  Hits          163      163           
  Misses         18       18           
  Partials        9        9

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[bbatsov]

That's a good point, but I'm not sure how to best document it. Generally we operated with the assumption that ClojureScript would be provided by the user's environment and opted not to hardcode a dependency on it that sometimes might be problematic (e.g. outdated). I agree we should probably write something, but I'm not sure what exactly.

@cichli @dpsutton @bhauman Any thoughts on this?

[duncanjbrown]

Thank you @bbatsov. I felt a bit awkward about that too.

If users are asked to add it to their deps.edn then I guess the work of deciding which version to include is already on their plate anyway. So a possible solution is to say "Alternatively, you can pass the dependency to clj by adding an -Sdeps option to the above command"?

[SevereOverfl0w]

I've been wanting to raise a similar issue to this, I was going to look into making piggieback disable itself if cljs isn't available

[bbatsov]

This was addressed by #106.