EditorManager: Remove QString openEditor(At) overloads

In favor of the FilePath/Link ones.

Change-Id: I5caf9e0f8de304ff4ee12329557aa50a6f3a0c69
Reviewed-by: Qt CI Bot <qt_ci_bot@qt-project.org>
Reviewed-by: David Schulz <david.schulz@qt.io>

src/plugins/vcsbase/vcsoutputwindow.cpp

@@ -203,7 +203,7 @@ void OutputWindowPlainTextEdit::contextMenuEvent(QContextMenuEvent *event)
             return;
         }
         if (action == openAction) {
-            const QString fileName = action->data().toString();
+            const auto fileName = Utils::FilePath::fromVariant(action->data());
             Core::EditorManager::openEditor(fileName);
         }
     }