ClangCodeModel: Implement global renaming via clangd

Note that we do not use the LSP rename functionality. We do "manual"
renaming the same way as in the built-in code model, but based on the
references found by clangd.

Change-Id: Ifa5597efe5c89c8f9204a4f5323bc755544696cf
Reviewed-by: Qt CI Bot <qt_ci_bot@qt-project.org>
Reviewed-by: David Schulz <david.schulz@qt.io>

src/plugins/clangcodemodel/clangdclient.h

@@ -26,6 +26,7 @@
 #pragma once
 
 #include <languageclient/client.h>
+#include <utils/optional.h>
 
 #include <QVersionNumber>
 
@@ -49,7 +50,8 @@ public:
     void openExtraFile(const Utils::FilePath &filePath, const QString &content = {});
     void closeExtraFile(const Utils::FilePath &filePath);
 
-    void findUsages(TextEditor::TextDocument *document, const QTextCursor &cursor);
+    void findUsages(TextEditor::TextDocument *document, const QTextCursor &cursor,
+                    const Utils::optional<QString> &replacement);
 
     void enableTesting();