Fix miniarena

src/arena.c

@@ -132,9 +132,9 @@ void arena_reset_to(Arena *arena, U64 total_offset)
     }
 }
 
-ArenaCheckpoint arena_temp_begin(Arena *arena)
+ATemp arena_temp_begin(Arena *arena)
 {
-    ArenaCheckpoint checkpoint = {};
+    ATemp checkpoint = {};
     checkpoint.arena           = arena;
     checkpoint.total_offset    = arena_used(arena);
     arena->checkpoint_level++;
@@ -142,7 +142,7 @@ ArenaCheckpoint arena_temp_begin(Arena *arena)
     return checkpoint;
 }
 
-void arena_temp_end(ArenaCheckpoint *checkpoint)
+void arena_temp_end(ATemp *checkpoint)
 {
     Arena *arena = checkpoint->arena;
     Assert(arena->checkpoint_level > 0);