dtoh: Don't use enum namespaces as types

[MoonlightSentinel]

Use the base type for variables/parameters/... when the enum was emitted as a namespace.

[dlang-bot]

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Bugzilla references

Auto-close	Bugzilla	Severity	Description
✓	21300	normal	C++ header generation produce nonsense code on enum with enum as parent

Testing this PR locally

If you don't have a local development environment setup, you can use Digger to test this PR:

dub run digger -- build "master + dmd#11906"