ClangCodeModel: Adapt to updated clangd tooltip format

The header file path is not the last line anymore;
see https://reviews.llvm.org/D146244.

Change-Id: Ifbc2b55c0a82c661454d487c287fe4fb5a950d38
Reviewed-by: Qt CI Bot <qt_ci_bot@qt-project.org>
Reviewed-by: <github-actions-qt-creator@cristianadam.eu>
Reviewed-by: David Schulz <david.schulz@qt.io>

src/plugins/clangcodemodel/clangdclient.cpp

@@ -1069,9 +1069,8 @@ void ClangdClient::gatherHelpItemForTooltip(const HoverRequest::Response &hoverR
                 QString cleanString = markupString;
                 cleanString.remove('`');
                 const QStringList lines = cleanString.trimmed().split('\n');
-                if (!lines.isEmpty()) {
-                    const auto markupFilePath = Utils::FilePath::fromUserInput(
-                        lines.last().simplified());
+                for (const QString &line : lines) {
+                    const auto markupFilePath = Utils::FilePath::fromUserInput(line.simplified());
                     if (markupFilePath.exists()) {
                         d->setHelpItemForTooltip(hoverResponse.id(),
                                                  filePath,