Fix Issue 23308 - void* and T* not merged properly

[maxhaton]

Slightly speculative.

Fixing the merging of types fixes the overload resolution bug for some reason

[dlang-bot]

Thanks for your pull request, @maxhaton!

Bugzilla references

Auto-close	Bugzilla	Severity	Description
✓	23308	normal	Can't resolve overload of varargs function if one parameter is the result of a ternary expression

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#14396"