Add AllowParenthesesInCamelCaseMethod option

[dazuma]

This adds the option AllowParenthesesInCamelCaseMethod to the Style/MethodCallWithArgsParentheses cop, which takes effect when EnforcedStyle: omit_parentheses. When this option is set to true, methods whose name begins with a capital letter (i.e. which look like constants/modules) may be called using parentheses even when taking arguments. When this option is set to false (the default, and identical to previous behavior), such methods may be called using parentheses when taking no arguments but must omit the parentheses when taking arguments.

This style (always using parens when calling such methods) is useful in the omit_parentheses case because even though it is not actually syntactically ambiguous when arguments are present, it still it makes it syntactically more obvious that a method is being called rather than a constant being invoked.

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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.

[Drenmi]

More specifically, this is PascalCase, not camelCase? 🙂

[dazuma]

@Drenmi This is true. (Or I've also seen the term UpperCamelCase.)

The naming I've chosen, however, follows the existing internal naming convention (i.e. the existing methods refer to these simply as "camel_case_method_calls".) Additionally, it seems that when the term "camel-case" is used in the Ruby community, it most often refers specifically to UpperCamelCase, because that convention is actually used in the Ruby language conventions (whereas lowerCamelCase is not). A good example is ActiveSupport's "camelize" in which the default option is upper.

[Drenmi]

I'm okay with this addition. I just cut a new release, so you'll need to rebase this on the latest version of master, and fix the CHANGELOG. 🙂

Thank you for your contribution! 🙇

[dazuma]

Thanks much! Rebased and resolved conflicts. bundle update && bundle exec rake default is clean on Ruby 2.5.3.