Support Swift syntax 602

[gsabran]

While upgrading to Swift 6.2, I was running into issues such as

duplicate symbol 'protocol conformance descriptor for SwiftSyntax.GenericParameterClauseSyntax : SwiftSyntax._LeafSyntaxNodeProtocol in SwiftSyntax' in:
    ./modules/.build/arm64-apple-macosx/debug/SwiftSyntax-tool.build/SyntaxNodesGHI.swift.o
    ./modules/.build/prebuilts/swift-syntax/600.0.1/swiftlang-6.2.0.19.9-MacroSupport-macos_aarch64/lib/libMacroSupport.a[168](SyntaxNodesGHI.swift.o)

which I believe relate to the new pre-built in swift syntax that shipped with Swift 6.2.

After upgrading all my dependencies to Swift syntax 602, the error was gone.

If that change sounds good to you, I'll make similar PRs in your other repos that all depend on each other (dependencies, macro testing for what I know of)

[stephencelis]

Thanks! #1023 beat you to the punch, but we'll merge/release things soon!