docs: Fix typo in Using Calculator learn notebook

[kratsg]

Pull Request Description

Thanks to @madbaron for the catch.

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• Tests are passing
• "WIP" removed from the title of the pull request
• Selected an Assignee for the PR to be responsible for the log summary

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* Use the ToyCalculator API for computing the pvalues/expected pvalues in the 'Toy-Based' section
* Update returns to match v0.6.0 API of 0-d tensors

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Codecov Report

Merging #1331 (d130080) into master (9ee94f1) will not change coverage.
The diff coverage is n/a.

@@           Coverage Diff           @@
##           master    #1331   +/-   ##
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  Coverage   97.50%   97.50%           
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  Files          63       63           
  Lines        3760     3760           
  Branches      538      538           
=======================================
  Hits         3666     3666           
  Misses         55       55           
  Partials       39       39           

Flag	Coverage Δ
unittests	97.50% <ø> (ø)

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[matthewfeickert]

LGTM. Thanks very much @kratsg and thank you very much for reporting @madbaron!