Prefer prefix operator

Change-Id: I44934f66b11fc537045df1d15fe98844ee7045ca
Reviewed-on: https://gerrit.libreoffice.org/42370Tested-by: Jenkins <ci@libreoffice.org>
Reviewed-by: Julien Nabet <serval2412@yahoo.fr>

sw/source/uibase/dbui/dbmgr.cxx

@@ -3217,7 +3217,7 @@ void SwDBManager::RevokeLastRegistrations()
                 it = m_aUncommitedRegistrations.erase(it);
             }
             else
-                it++;
+                ++it;
         }
     }
 }