[clang-tools-extra] [clang-tidy] Enhance modernize-use-starts-ends-with to handle substr patterns (PR #116033)

[Nicolas van Kempen via cfe-commits]

================
@@ -71,6 +71,17 @@ struct NotLengthExprForStringNode {
   ASTContext *Context;
 };
 
+static bool isNegativeComparison(const Expr *ComparisonExpr) {
+  if (const auto *BO = llvm::dyn_cast<BinaryOperator>(ComparisonExpr)) {
+    return BO->getOpcode() == BO_NE;
+  }
+
+  if (const auto *Op = llvm::dyn_cast<CXXOperatorCallExpr>(ComparisonExpr)) {
+    return Op->getOperator() == OO_ExclaimEqual;
+  }
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nicovank wrote:

```suggestion
  if (const auto *Op = llvm::dyn_cast<CXXOperatorCallExpr>(ComparisonExpr))
    return Op->getOperator() == OO_ExclaimEqual;

```

https://github.com/llvm/llvm-project/pull/116033