Sc_Obligations: add support for the new Side_Effects pragma

(cherry picked from commit f82c5ee)

Author: pmderodat

tools/gnatcov/sc_obligations.ads

@@ -973,6 +973,7 @@ package SC_Obligations is
       Pragma_Shared_Passive,
       Pragma_Short_Circuit_And_Or,
       Pragma_Short_Descriptors,
+      Pragma_Side_Effects,
       Pragma_Simple_Storage_Pool_Type,
       Pragma_Source_File_Name,
       Pragma_Source_File_Name_Project,
@@ -1239,6 +1240,7 @@ package SC_Obligations is
           Pragma_Share_Generic => False,
           Pragma_Shared => False,
           Pragma_Shared_Passive => False,
+          Pragma_Side_Effects => False,
           Pragma_Simple_Storage_Pool_Type => False,
           Pragma_Source_Reference => False,
           Pragma_Static_Elaboration_Desired => False,