Fix issue 24075 - Can't use toChars with ushort or ubyte

[eoan-ermine]

No description provided.

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Bugzilla references

Auto-close	Bugzilla	Severity	Description
✓	24075	enhancement	Can't use toChars with `ushort` or `ubyte`

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 + phobos#8866"

[dkorpel]

I wish it would just promote the integer instead of instantiating a new Result struct for each integral type, but that's an enhancement for a future PR