Bazaar, Cvs, Fossil, Mercurial, Perforce, Svn: Simplify returns

Change-Id: Ic0d6a7510a26a4a9db180594f140156b036c5090
Reviewed-by: Orgad Shaneh <orgads@gmail.com>

src/plugins/bazaar/annotationhighlighter.cpp

@@ -19,7 +19,7 @@ QString BazaarAnnotationHighlighter::changeNumber(const QString &block) const
     const QRegularExpressionMatch match = m_changeset.match(block);
     if (match.hasMatch())
         return match.captured(1);
-    return QString();
+    return {};
 }
 
 } // Bazaar::Internal