missing_docs doesn't trigger for non-inherited properties/functions when using excludes_inherited_types

[bobbradley]

New Issue Checklist

• [x] Updated SwiftLint to the latest version
• [x] I searched for existing GitHub issues

Describe the bug

If missing_docs is enabled and excludes_inherited_types is true then undocumented and non-inherited public properties/functions don't trigger missing_docs warnings if the type inherits from a protocol. For example:

/// My type.
public struct MyType: Identifiable {
    public id: String // No warning expected here because this property comes from `Identifiable`.

    // Warning expected here because it's not inherited from `Identifiable`, but warning is not reported.
    public name: String
}

Complete output when running SwiftLint, including the stack trace and command used

$ swiftlint lint
Linting Swift files in current working directory
Linting 'Test.swift' (1/1)
Done linting! Found 0 violations, 0 serious in 1 file.

Environment

• SwiftLint version: 0.55.1
• Installation method used: Homebrew
• Paste your configuration file:

opt_in_rules:
  - missing_docs

missing_docs:
  excludes_inherited_types: true

• Are you using nested configurations? No
• Which Xcode version are you using (check xcodebuild -version)? Reproduces without Xcode.
• Do you have a sample that shows the issue? Yes:

/// My type.
public struct MyType: Identifiable {
    public id: String // No warning expected here because this property comes from `Identifiable`.

    // Warning expected here because it's not inherited from `Identifiable`, but warning is not reported.
    public name: String
}

[SimplyDanny]

SwiftLint works on the syntax level only. So it doesn't know which declarations exactly stem from a protocol or parent class. This is why excludes_inherited_types exists and, with it enabled, the rule ignores inheriting types completely.