Missing brief descriptions with `\defgroup`

Due to the fact that issue #6945 ended a brief description, all following was put into the detailed description (unless explicit \brief was used). The `\defgroup` should end the current brief description, but first line of the `\defgroup` should be seen as a new brief description.
Problem can be seen with in the doxygen documentation in the example in the Grouping part and also with #7053 a small example is given in the comment.

1 files changed, 1 insertions, 0 deletions

diff --git a/src/commentscan.l b/src/commentscan.l
index e75d023..a7dc6d3 100644
--- a/src/commentscan.l
+++ b/src/commentscan.l
@@ -2359,6 +2359,7 @@ static bool handleDefGroup(const QCString &, const QCStringList &)
 {
   bool stop=makeStructuralIndicator(Entry::GROUPDOC_SEC);
   current->groupDocType = Entry::GROUPDOC_NORMAL;
+  setOutput(OutputBrief);
   BEGIN( GroupDocArg1 );
   return stop;
 }