* `string-list-and-dict-methods` cleanup

also some formatting fixes

* `import-callables-from-operator` cleanup

also more formatting fixes

* `regex-with-operator-module` cleanup

* `lambdas-in-a-dictionary` cleanup

* `recursion` approach cleanup

* add warning about `recursion` variation 2

* clean up the rest of the approaches

* fix minor errors in approaches

* Apply suggestion from code review

Co-authored-by: BethanyG
<BethanyG@users.noreply.github.com>

* add additional tests for long questions

* add self to contributors array

* add `tuple-and-index` approach

also add "None" link and a few minor fixes

* make wording more clear in fifth paragraph

* Apply suggestions from code review

Co-authored-by: BethanyG <BethanyG@users.noreply.github.com>

* Improve line 70

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Co-authored-by: BethanyG <BethanyG@users.noreply.github.com>

)

* fix benchmark & add timings for new approach

* update "measurements were taken on" part

* improve performance article

* fix the performance article's `config.json`

* add approach docs for new approach

* Apply suggestions from code review

Co-authored-by: BethanyG <BethanyG@users.noreply.github.com>

* minor fixes

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Co-authored-by: BethanyG <BethanyG@users.noreply.github.com>