[Issue 24611] Cannot explicitly instantiate template function with `auto ref`

[d-bugmail at puremagic.com]

https://issues.dlang.org/show_bug.cgi?id=24611

--- Comment #1 from Bolpat <qs.il.paperinik at gmail.com> ---
Grammar change needed for the suggested fix:
```diff
    TemplateArgument:
        Type
+       ref Type
        AssignExpression
        Symbol
```

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