TextEditor: De-virtual executeSearch

Git Grep is now implemented as an extension, instead of by inheritance.

Change-Id: Idec79ec167a3ca35d87deb2d0e16e134f093b67f
Reviewed-by: Eike Ziller <eike.ziller@theqtcompany.com>

src/plugins/texteditor/basefilefind.h

@@ -102,8 +102,7 @@ protected:
     virtual QString label() const = 0; // see Core::SearchResultWindow::startNewSearch
     virtual QString toolTip() const = 0; // see Core::SearchResultWindow::startNewSearch,
                                          // add %1 placeholder where the find flags should be put
-    virtual QFuture<Utils::FileSearchResultList> executeSearch(
-            const FileFindParameters &parameters);
+    QFuture<Utils::FileSearchResultList> executeSearch(const FileFindParameters &parameters);
 
     void writeCommonSettings(QSettings *settings);
     void readCommonSettings(QSettings *settings, const QString &defaultFilter);