Prevent empty cheek stations for the Hornet.

This is a bit of a hack that makes the TGPs fall back to AIM-120s. It
works okay because this only applies to a few cases:

The A-10 gets an empty pylon. That's fine. Maybe later we can add
multiple fallback paths and depth-first-search through them so that that
pylon could carry bombs instead.

The Viper has no replacemnt for that station. The jammer goes on the
other fuselage station, the HTS isn't a replacement, and we don't have
LANTIRN for the Viper. No weapons can be fit to those stations.

What this helps is the Hornet, where any Gulf War scenario ends up with
an empty cheek station because we don't have the NITE HAWK to fall back
to. In this case we can instead fall back through the air-to-air
missiles to fill the station.

resources/weapons/pods/atflir.yaml

@@ -1,4 +1,7 @@
 name: AN/ASQ-228 ATFLIR
 year: 2003
+# A bit of a hack, but fixes the common case where the Hornet cheek station is
+# empty because no TGP is available.
+fallback: AIM-120C
 clsids:
   - "{AN_ASQ_228}"

resources/weapons/pods/litening.yaml

@@ -1,5 +1,14 @@
 name: AN/AAQ-28 LITENING
 year: 1999
+# A bit of a hack, but fixes the common case where the Hornet cheek station is
+# empty because no TGP is available. For the Viper this will have no effect
+# because missiles can't be put on that station, but for the Viper an empty
+# pylon is the correct replacement for a TGP anyway (the jammer goes on the
+# other fuselage station, HTS isn't a good replacement, and we don't have
+# LANTIRN for the Viper).
+#
+# For the A-10 an empty pylon is also fine.
+fallback: AIM-120C
 clsids:
   - "{A111396E-D3E8-4b9c-8AC9-2432489304D5}"
   - "{AAQ-28_LEFT}"