feat: hashmap with_capacity

src/ty/internal/attrset.rs

@@ -1,3 +1,5 @@
+use std::hash::Hash;
+
 use hashbrown::{HashMap, HashSet};
 
 use derive_more::Constructor;
@@ -22,6 +24,10 @@ impl<'vm> AttrSet<'vm> {
         }
     }
 
+    pub fn with_capacity(cap: usize) -> Self {
+        AttrSet { data: HashMap::with_capacity(cap) }
+    }
+
     pub fn push_attr_force(&mut self, sym: usize, val: Value<'vm>) {
         self.data.insert(sym, val);
     }