Support multiple arguments on Lint/SendWithMixinArgument

[r7kamura]

These mixin methods can take multiple arguments, so these patterns should also be supported in this cop.

• Module#include
• Module#prepend
• Object#extend

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Before submitting the PR make sure the following are checked:

• The PR relates to only one subject with a clear title and description in grammatically correct, complete sentences.
• 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.
• Ran bundle exec rake default. It executes all tests and runs RuboCop on its own code.
• Added an entry (file) to the changelog folder named {change_type}_{change_description}.md if the new code introduces user-observable changes. See changelog entry format for details.

[r7kamura]

This may be a trivial point, but I chose change as the category for the CHANGELOG entry because I figured that some existing users would expect it to work only with one argument. If another category is more appropriate, please let me know. (This may be fix if you strongly believe it should have been supported, or new if you believe it is a feature addition)

[koic]

Looks good to me!