Fix typo in forbidden group for R_Recombination

Author: nyee

input/kinetics/families/R_Recombination/groups.py

@@ -1423,7 +1423,7 @@
     label = "Cl_2",
     group = 
 """
-1 *12 Cl u1
+1 *2 Cl u1
 """,
     shortDesc = u"""""",
     longDesc =