[clang] [flang] [flang] Add UNSIGNED (PR #113504)

[Peter Klausler via cfe-commits]

klausler wrote:

> Seems a place that needs to add UNSIGNED type case
> 
> ```
> llvm-project/flang/lib/Semantics/resolve-names.cpp:7597:16: error: enumeration value 'Unsigned' not handled in switch [-Werror,-Wswitch]
>   switch (type.category()) {
>           ~~~~~^~~~~~~~~~
> llvm-project/flang/lib/Semantics/resolve-names.cpp:7621:1: error: non-void function does not return a value in all control paths [-Werror,-Wreturn-type]
> }
> ```

Thanks, added a case.

https://github.com/llvm/llvm-project/pull/113504