Regarding the proposed Binray Literals Deprecation

[Tejas]

On Saturday, 10 September 2022 at 21:57:51 UTC, Timon Gehr wrote:
> On 10.09.22 19:43, Walter Bright wrote:
>> [...]
>
> 422 is a decimal literal. E.g., there is type deduction logic 
> in the compiler:
>
> [...]

I always thought we have user defined literals thanks to UFCS. 
Stuff like `3.seconds`, `27.metres`. What do user defined 
literals used via templates that take `string` arguments look 
like?