Rule Request: Enforce multiple protocol inheritance style

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• Updated SwiftLint to the latest version
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New rule request

There are two ways to inherit from multiple protocols:

protocol Foo: Hashable, Identifiable {}
protocol Foo: Hashable & Identifiable {}

Source: https://forums.swift.org/t/is-this-a-good-idea-protocol-identifiablehashable-hashable-identifiable/47496/11

1. Why should this rule be added? Share links to existing discussion about what
   the community thinks about this.

It would be good to be able to enforce a style to make code more consistent.

2. Provide several examples of what would and wouldn't trigger violations.

That depends on which style you choose.

Either of these would trigger:

protocol Foo: Hashable, Identifiable {}
protocol Foo: Hashable & Identifiable {}

These would not trigger

protocol Foo: Identifiable {}
protocol Foo: Hashable {}

3. Should the rule be configurable, if so what parameters should be configurable?

Yes, you should be able to choose which style to use.

4. Should the rule be opt-in or enabled by default? Why?
   See README.md for guidelines on when to mark a rule as opt-in.

No

Start with the two protocol-inheritance examples and the linked Swift forum discussion, then review README.md's opt-in-rule guidelines. Before implementation, settle which style is enforced, how the choice is configured, and whether the rule is opt-in; done means those decisions are reflected in concrete triggering and non-triggering examples.