Fix Style/NestedParenthesizedCalls docs

[igor-drozdov]

method1(method2 arg, method3, arg) is not equivalent to method1(method2 arg, method3, arg)

method1(method2 arg, method3 arg) would be incorrect as well

method1(method2 arg) vs method1(method2(arg)) would be an example that illustrates the code standards and is correct in terms of syntax

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Before submitting the PR make sure the following are checked:

• Wrote good commit messages.
• Commit message starts with [Fix #issue-number] (if the related issue exists).
• Feature branch is up-to-date with master (if not - rebase it).
• Squashed related commits together.
• Added tests.
• Added an entry to the Changelog if the new code introduces user-observable changes. See changelog entry format.
• The PR relates to only one subject with a clear title and description in grammatically correct, complete sentences.
• Run bundle exec rake default. It executes all tests and RuboCop for itself, and generates the documentation.

[koic]

CI has failed. Can you run rake generate_cops_documentation and apply it?

[koic]

This looks good to me. Can you squash your commits into one?

[bbatsov]

I squashed on merge.