[clang] [clang-format] Do not update cursor pos if no includes replacement (PR #77456)

[Owen Pan via cfe-commits]

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@@ -3123,6 +3123,7 @@ static void sortCppIncludes(const FormatStyle &Style,
   }
 
   std::string result;
+  unsigned NewCursor = UINT_MAX;
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owenca wrote:

```suggestion
  const auto OldCursor = Cursor ? *Cursor : 0;
```

https://github.com/llvm/llvm-project/pull/77456