False Positive: `_modify` for analyzer rules

New Issue Checklist

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

Describe the bug

When using the unused_declarations analyze rule, I noticed that _modify blocks are erroneously triggering the analyzer; that would be akin to a get or set block triggering the analyzer.

Note that when we scan it for errors, declarations like this will produce an error on the _modify keyword:

  @inlinable public subscript<T: AnyScalarType & Hashable>(_ key: String) -> T {
    get {
#if swift(>=5.4)
        _data[key] as! T
#else
        _data[key]?.base as! T
#endif
    }
    set { _data[key] = newValue }
    _modify {
      var value = _data[key] as! T
      defer { _data[key] = value }
      yield &value
    }
  }

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

$ ➜ swiftlint analyze --compiler-log-path xcodebuild.log

It's quite long, so I'll just filter it for the errors:

/Users/zer0/Developer/OSS/apollo-ios/Sources/Apollo/GraphQLHTTPMethod.swift:1:1: warning: Unused Import Violation: All imported modules should be required to make the file compile (unused_import)
/Users/zer0/Developer/OSS/apollo-ios/Sources/Apollo/Collection+Helpers.swift:1:1: warning: Unused Import Violation: All imported modules should be required to make the file compile (unused_import)
/Users/zer0/Developer/OSS/apollo-ios/Sources/Apollo/PossiblyDeferred.swift:1:1: warning: Unused Import Violation: All imported modules should be required to make the file compile (unused_import)
/Users/zer0/Developer/OSS/apollo-ios/Sources/Apollo/NormalizedCache.swift:1:1: warning: Unused Import Violation: All imported modules should be required to make the file compile (unused_import)
/Users/zer0/Developer/OSS/apollo-ios/Sources/Apollo/SelectionSet+JSONInitializer.swift:1:1: warning: Unused Import Violation: All imported modules should be required to make the file compile (unused_import)
/Users/zer0/Developer/OSS/apollo-ios/Sources/Apollo/GraphQLSelectionSetMapper.swift:5:1: warning: Unused Import Violation: All imported modules should be required to make the file compile (unused_import)
/Users/zer0/Developer/OSS/apollo-ios/Sources/Apollo/RequestChain.swift:1:1: warning: Unused Import Violation: All imported modules should be required to make the file compile (unused_import)
/Users/zer0/Developer/OSS/apollo-ios/Sources/Apollo/RequestBodyCreator.swift:1:1: warning: Unused Import Violation: All imported modules should be required to make the file compile (unused_import)
/Users/zer0/Developer/OSS/apollo-ios/Sources/Apollo/InMemoryNormalizedCache.swift:1:1: warning: Unused Import Violation: All imported modules should be required to make the file compile (unused_import)
/Users/zer0/Developer/OSS/apollo-ios/Sources/Apollo/DataLoader.swift:1:1: warning: Unused Import Violation: All imported modules should be required to make the file compile (unused_import)
/Users/zer0/Developer/OSS/apollo-ios/Sources/Apollo/HTTPURLResponse+Helpers.swift:8:7: error: Unused Declaration Violation: Declarations should be referenced at least once within all files linted (unused_declaration)
/Users/zer0/Developer/OSS/apollo-ios/Sources/Apollo/DispatchQueue+Optional.swift:1:1: warning: Unused Import Violation: All imported modules should be required to make the file compile (unused_import)
/Users/zer0/Developer/OSS/apollo-ios/Sources/Apollo/GraphQLResult.swift:1:1: warning: Unused Import Violation: All imported modules should be required to make the file compile (unused_import)
/Users/zer0/Developer/OSS/apollo-ios/Sources/ApolloAPI/InputValue.swift:1:1: warning: Unused Import Violation: All imported modules should be required to make the file compile (unused_import)
/Users/zer0/Developer/OSS/apollo-ios/Sources/ApolloAPI/LocalCacheMutation.swift:39:5: error: Unused Declaration Violation: Declarations should be referenced at least once within all files linted (unused_declaration)
/Users/zer0/Developer/OSS/apollo-ios/Sources/ApolloAPI/LocalCacheMutation.swift:1:1: warning: Unused Import Violation: All imported modules should be required to make the file compile (unused_import)
/Users/zer0/Developer/OSS/apollo-ios/Sources/ApolloAPI/DataDict.swift:35:5: error: Unused Declaration Violation: Declarations should be referenced at least once within all files linted (unused_declaration)
/Users/zer0/Developer/OSS/apollo-ios/Sources/ApolloAPI/DataDict.swift:45:5: error: Unused Declaration Violation: Declarations should be referenced at least once within all files linted (unused_declaration)
/Users/zer0/Developer/OSS/apollo-ios/Sources/ApolloAPI/JSON.swift:1:1: warning: Unused Import Violation: All imported modules should be required to make the file compile (unused_import)
/Users/zer0/Developer/OSS/apollo-ios/Sources/ApolloAPI/GraphQLNullable.swift:1:1: warning: Unused Import Violation: All imported modules should be required to make the file compile (unused_import)
/Users/zer0/Developer/OSS/apollo-ios/Sources/ApolloAPI/AnyHashableConvertible.swift:1:1: warning: Unused Import Violation: All imported modules should be required to make the file compile (unused_import)
/Users/zer0/Developer/OSS/apollo-ios/Sources/ApolloAPI/Selection.swift:1:1: warning: Unused Import Violation: All imported modules should be required to make the file compile (unused_import)
/Users/zer0/Developer/OSS/apollo-ios/Sources/ApolloAPI/Selection+Conditions.swift:1:1: warning: Unused Import Violation: All imported modules should be required to make the file compile (unused_import)

Environment

• SwiftLint version (run swiftlint version to be sure)? 0.52.3
• Installation method used (Homebrew, CocoaPods, building from source, etc)? Brew
• Paste your configuration file:

analyzer_rules:
  - unused_import
  - unused_declaration

• Which Xcode version are you using (check xcodebuild -version)? 14.3.1

  @inlinable public subscript<T: AnyScalarType & Hashable>(_ key: String) -> T {
    get {
#if swift(>=5.4)
        _data[key] as! T
#else
        _data[key]?.base as! T
#endif
    }
    set { _data[key] = newValue }
    _modify {
      var value = _data[key] as! T
      defer { _data[key] = value }
      yield &value
    }
  }

Start by running swiftlint analyze --compiler-log-path xcodebuild.log with the unused_declaration analyzer rule against the provided subscript containing _modify. Trace how the analyzer handles get and set blocks versus _modify, then add coverage for the sample and verify that _modify no longer produces a false positive.