[Fix #7900] Fix Style/FormatStringToken false positive with formatted input and template style enforced, and add autocorrection

[FnControlOption]

Fixes #7900.

Types of format strings:

• annotated: '%<name>s' (where s is the format type)
• template: '%{name}'
• unannotated: '%s'

The format string '%{name}' is only equivalent to '%<name>s', so when enforcing the template style, no offenses should be reported if the format type is not s (for example, '%<name>f').

The autocorrection from template style %[flags][width][.precision]{name} to annotated style is %<name>[flags][width][.precision]s, and vice versa.

Because unannotated has no names, it can't be autocorrected to annotated or template.

Autocorrecting from either annotated or template to unannotated is possible, but I haven't attempted adding this yet. The method arguments must be updated too, so def on_send would need to be added (maybe as a new cop). For example:

format('%<greeting>s', greeting: 'Hello')
format('%{foo} %{bar} %{foo}', foo: 'foo', bar: 'bar')
# becomes
format('%s', 'Hello')
format('%1$s %2$s %1$s', 'foo', 'bar')

---

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• 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).
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• 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.

[FnControlOption]

I realized that these lines can be simplified to:

return if style == :unannotated || detected_sequence.style == :unannotated

name = detected_sequence.name
flags = detected_sequence.flags
width = detected_sequence.width
precision = detected_sequence.precision
type = case detected_sequence.style
       when :annotated then detected_sequence.type
       when :template then 's'
       end

[marcandre]

Looks good to me 👍