[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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@@ -53,13 +55,38 @@ struct RenameInputs {
 struct RenameResult {
   // The range of the symbol that the user can attempt to rename.
   Range Target;
+  // Placeholder text for the rename operation, if set.
+  std::optional<std::string> Placeholder;
   // Rename occurrences for the current main file.
   std::vector<Range> LocalChanges;
   // Complete edits for the rename, including LocalChanges.
   // If the full set of changes is unknown, this field is empty.
   FileEdits GlobalChanges;
 };
 
+/// Represents a symbol range where the symbol can potentially have multiple
+/// tokens.
+struct SymbolRange {
+  /// All ranges. If multiple, corresponds to an ObjC selector.
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kadircet wrote:

maybe also talk about the general case?
```
Ranges for the tokens that make up the symbol's name.
Usually a single range, there can be multiple ranges if the tokens for symbol are split, e.g. ObjC selectors.
```

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