Fix defunct error message bug

[malcolmbarrett]

Summary

When functions marked defunct using drake_defunct include drake::, the call -> string conversion results in a mangled message

drake::analyses()
#> Error: function ::() in drake is defunct.function drake() in drake is defunct.function analyses() in drake is defunct.

^{Created on 2020-08-26 by the reprex package (v0.3.0)}

• This PR deparses match.call() prior to pasting. (rlang can also do this but I chose deparse() because there seems to be some discussion about long-term deprecation of quo_text() and cousins in favor of a different approach, and this struck me as too simple a problem to deal with it.)
• I also added a test for this bug.

With the PR, the output is now correct:

drake::analyses()
#> Error: function drake::analyses() in drake is defunct.

^{Created on 2020-08-26 by the reprex package (v0.3.0)}

Checklist

• I understand and agree to drake's code of conduct.
• I have listed any substantial changes in the development news.
• I have added testthat unit tests to tests/testthat for any new functionality.
• This pull request is not a draft.

[codecov-commenter]

Codecov Report

Merging #1310 into master will not change coverage.
The diff coverage is 100.00%.

@@            Coverage Diff            @@
##            master     #1310   +/-   ##
=========================================
  Coverage   100.00%   100.00%           
=========================================
  Files           51        51           
  Lines         8324      8327    +3     
=========================================
+ Hits          8324      8327    +3     

Impacted Files	Coverage Δ
R/defunct.R	100.00% <100.00%> (ø)

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[wlandau]

Thanks for catching this, @malcolmbarrett! Would you use drake's safe_deparse() instead of base::deparse() and mention your patch in NEWS.md?

[malcolmbarrett]

Ah, I should have known that drake would have an opinion on deparsing! Done.

[wlandau]

Thanks!

Don’t worry about the GitHub Actions errors, those are transient and unrelated.