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`.

history.cpp

@@ -689,7 +689,7 @@ EX namespace history {
   auto hookArg = addHook(hooks_args, 100, readArgs);
   #endif  
 
-  auto hooks = addHook(clearmemory, 0, [] () {
+  auto hooks = addHook(hooks_clearmemory, 0, [] () {
     history::renderAutoband();
     history::on = false;
     history::killhistory.clear();