Fix Issue 16181 - Overloading doesn't consider default arguments with…

[Luhrel]

… regards to ambiguity

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Bugzilla references

Auto-close	Bugzilla	Severity	Description
✓	16181	minor	Overloading doesn't consider default arguments with regards to ambiguity

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#11127"

[kubo39]

should it be deprecation?

[kubo39]

NIT: c1 and c2 can be moved here.

[WalterBright]

It is not a bug and the compiler is behaving as designed.

[WalterBright]

Sorry.