[clang-tools-extra] [clang-tidy] Fix invalid fixit from modernize-use-ranges for nullptr used with std::unique_ptr (PR #127162)

[Piotr Zegar via cfe-commits]

================
@@ -215,6 +215,16 @@ void UseRangesCheck::check(const MatchFinder::MatchResult &Result) {
     const auto *Call = Result.Nodes.getNodeAs<CallExpr>(Buffer);
     if (!Call)
       continue;
+    if (Function->getName() == "find") {
+      unsigned ValueArgIndex = 2;
----------------
PiotrZSL wrote:

```suggestion
      const unsigned ValueArgIndex = 2;
```

https://github.com/llvm/llvm-project/pull/127162