[clang] [lldb] [lldb] Re-use clang's keyword enable/disable mechanism in CPlusPlusNameParser.cpp (PR #164284)

[Michael Buch via cfe-commits]

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Michael137 wrote:

very minor nit, but could we move this `using namespace` down to just before the macro. Just so it gives the reader some indication that we may be using it for the `include` machinery

https://github.com/llvm/llvm-project/pull/164284