[docs][OpenMP] Claim groupprivate for flang (llvm#153586)

Author: kparzysz

clang/docs/OpenMPSupport.rst

@@ -476,7 +476,7 @@ implementation.
 +-------------------------------------------------------------+---------------------------+---------------------------+--------------------------------------------------------------------------+
 | Local clause on declare target                              | :part:`In Progress`       | :none:`unclaimed`         |                                                                          |
 +-------------------------------------------------------------+---------------------------+---------------------------+--------------------------------------------------------------------------+
-| groupprivate directive                                      | :part:`In Progress`       | :none:`unclaimed`         |                                                                          |
+| groupprivate directive                                      | :part:`In Progress`       | :part:`In Progress`       | Flang: kparzysz, mjklemm                                                 |
 +-------------------------------------------------------------+---------------------------+---------------------------+--------------------------------------------------------------------------+
 | variable-category on default clause                         | :part:`In Progress`       | :none:`unclaimed`         |                                                                          |
 +-------------------------------------------------------------+---------------------------+---------------------------+--------------------------------------------------------------------------+