s/hb_prealloced_array_t/hb_vector_t/g

Part of https://github.com/harfbuzz/harfbuzz/issues/1017
diff --git a/src/hb-private.hh b/src/hb-private.hh
index a9a6bda..d7c8fef 100644
--- a/src/hb-private.hh
+++ b/src/hb-private.hh
@@ -527,7 +527,7 @@
 
 #define HB_PREALLOCED_ARRAY_INIT {0, 0, nullptr}
 template <typename Type, unsigned int StaticSize=16>
-struct hb_prealloced_array_t
+struct hb_vector_t
 {
   unsigned int len;
   unsigned int allocated;
@@ -710,14 +710,14 @@
   void fini (void) {}
 };
 template <typename Type>
-struct hb_auto_array_t : hb_auto_t <hb_prealloced_array_t <Type> > {};
+struct hb_auto_array_t : hb_auto_t <hb_vector_t <Type> > {};
 
 
 #define HB_LOCKABLE_SET_INIT {HB_PREALLOCED_ARRAY_INIT}
 template <typename item_t, typename lock_t>
 struct hb_lockable_set_t
 {
-  hb_prealloced_array_t <item_t, 1> items;
+  hb_vector_t <item_t, 1> items;
 
   inline void init (void) { items.init (); }