[clang] [clang][NFC] Run `modernize-use-using` check over all the code (PR #149934)

[Nikolas Klauser via cfe-commits]

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@@ -21,7 +21,7 @@ namespace driver {
 namespace tools {
 
 namespace mips {
-typedef enum { Legacy = 1, Std2008 = 2 } IEEE754Standard;
+using IEEE754Standard = enum { Legacy = 1, Std2008 = 2 };
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philnik777 wrote:

```suggestion
enum IEEE754Standard { Legacy = 1, Std2008 = 2 };
```

https://github.com/llvm/llvm-project/pull/149934