Forbid a charged carbene in singlet_carbene_intra_disproportionation

Forbidding a charged carbene such as in C[C-]=[N+]=O from reacting in
the singlet_carbene_intra_disproportionation family. See #213.

Author: alongd

input/kinetics/families/Singlet_Carbene_Intra_Disproportionation/groups.py

@@ -366,4 +366,17 @@
     L2: CH(C)C
     L2: CH=C
 """
-)
+)
+
+forbidden(
+    label = "charged_carbene",
+    group =
+"""
+1 *1 C u0 p1 c-1
+""",
+    shortDesc = u"""""",
+    longDesc =
+u"""
+
+""",
+)