[clang-tools-extra] Add support for renaming objc methods, even those with multiple selector pieces (PR #76466)

[kadir çetinkaya via cfe-commits]

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@@ -1436,6 +1436,14 @@ struct RenameParams {
 };
 bool fromJSON(const llvm::json::Value &, RenameParams &, llvm::json::Path);
 
+struct PrepareRenameResult {
+  /// Range of the string to rename.
+  Range range;
+  /// Placeholder text to use in the editor, if set.
+  std::optional<std::string> placeholder;
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kadircet wrote:

let's drop `optional` to prevent confusion here, there isn't any difference between an empty placeholder and nullopt, right?

https://github.com/llvm/llvm-project/pull/76466