replace calloc with mimalloc

src/main.zig

@@ -56,6 +56,9 @@ pub fn main() !void {
     var arena = std.heap.ArenaAllocator.init(std.heap.page_allocator);
     defer arena.deinit();
 
+    try parser.init();
+    defer parser.deinit();
+
     // document
     const file = try std.fs.cwd().openFile("test.html", .{});
     defer file.close();