Replace [Bool] with [Boolean] in method comments according to the YARD convention.

[jolyot]

This PR is to replace [Bool] with [Boolean] in method comments.

In the project, @param [Boolean] or @return [Boolean] and @param [Bool] or @return [Bool] are mixed up in the method comments, so the goal is to unify them into @param [Boolean] or @return [Boolean] according to the YARD convention.

[dnkoutso]

nice thanks! I wanted to do that at some point :) Can you also do one more PR for https://github.com/CocoaPods/Core?

[dnkoutso]

Looks like we need to fix CI.

Lint : .github#L1
The ubuntu-16.04 environment is deprecated and will be removed on September 20, 2021. Migrate to ubuntu-latest instead. For more details see https://github.com/actions/virtual-environments/issues/3287

I will do that in another PR now.

[dnkoutso]

CI fix here #10925 @jolyot you will have to rebase shortly once it lands.

[dnkoutso]

@jolyot all merged to master. Please rebase this PR so CI can start and we can land this! Thank you!

[jolyot]

@dnkoutso
I rebased this PR. And I opened a related PR for https://github.com/CocoaPods/Core.

[dnkoutso]

Merged core, will merge this one once its green.

[CocoaPodsBarista]

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* Replace [Bool] with [Boolean] in method comments  according to the YARD convention.  
  [jolyot](https://github.com/jolyot)
  [#issue_number](https://github.com/CocoaPods/CocoaPods/issues/issue_number)

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