fix step-before and step-after with dedicated test (#2340)

[tanganellilore]

Hi all

I request approval for this pull request for resolve the #2340 bug int he step chart with restore the "step-before" and "step-after" in the stop type graph.

I created a basic test for check if the graph works fine.
All test for my point of view are correctly ( I modify marginally the code of the graph).

For more usefull test I create two jsfiddle test
d3: v4.13.0 - https://jsfiddle.net/xjy7r25w/
d3: v5.4.0 - https://jsfiddle.net/p0qe247m/

Please accept this pull request.

Thanks
Lorenzo

[codecov-io]

Codecov Report

Merging #2385 into master will not change coverage.
The diff coverage is n/a.

@@           Coverage Diff           @@
##           master    #2385   +/-   ##
=======================================
  Coverage   77.23%   77.23%           
=======================================
  Files          51       51           
  Lines        4138     4138           
=======================================
  Hits         3196     3196           
  Misses        942      942

Impacted Files	Coverage Δ
src/shape.js	78.68% <ø> (ø)	⬆️

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[tanganellilore]

Hi @kt3k, @panthony and @masayuki0812,

can you approve this minimal change?
Thanks

[kt3k]

@tanganellilore
Thanks for the contribution! Sorry for the delayed response...

The change seems good and I confirmed 'step-after' and 'step-before' work for line.step.type 👍

The source code seems including tab indentation. Can you replace these with 4-space indent? (If you use editorconfig compliant editor, it automatically formats them correctly.

[tanganellilore]

Hi @kt3k ,

sorry for my mistake, I fix it!
I hadn't install editorconfig in my Visual Studio Code.

Now all is ok!

Thanks
Lorenzo

[kt3k]

Thanks for the quick update! LGTM 👍