Consistently name every hookset with prefix hooks_. NFC.

I'm sure this causes massive merge-conflicts in the non-public code,
but I think it'd be a good idea, if only to avoid confusion between
e.g. `clearMemory` and the-variable-formerly-known-as `clearmemory`.

complex.cpp

@@ -3418,7 +3418,7 @@ EX namespace ca {
     }
 EX }
 
-auto ccm = addHook(clearmemory, 0, [] () {
+auto ccm = addHook(hooks_clearmemory, 0, [] () {
   heat::offscreen_heat.clear();
   heat::offscreen_fire.clear();
   princess::clear();