Update getting-started.rst

[kevinsmia1939]

Update plot_nyquist to new plotting argument since the old one does not work anymore.

[coveralls]

Pull Request Test Coverage Report for Build 4251355906

• 0 of 0 changed or added relevant lines in 0 files are covered.
• No unchanged relevant lines lost coverage.
• Overall coverage remained the same at 100.0%

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Totals
Change from base Build 4226938388:	0.0%
Covered Lines:	848
Relevant Lines:	848

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💛 - Coveralls

[mdmurbach]

@all-contributors please add @kevinsmia1939 for docs

[allcontributors[bot]]

@mdmurbach

I've put up a pull request to add @kevinsmia1939! :tada: