Fix call to BitVec::ensure_vec_large_enough and add pub accessor

src/syn/bitstring.rs

@@ -101,15 +101,15 @@ impl BitVec {
     }
 
     pub fn set_bit(&mut self, bit: u64) {
-        self.ensure_vec_large_enough(bit);
+        self.ensure_vec_large_enough(bit + 1);
         let byte = bit / 8;
         let bit = bit % 8;
         let mask = 0x80_u8 >> bit;
         self.0[byte as usize] |= mask;
     }
 
     pub fn reset_bit(&mut self, bit: u64) {
-        self.ensure_vec_large_enough(bit);
+        self.ensure_vec_large_enough(bit + 1);
         let byte = bit / 8;
         let bit = bit % 8;
         let mask = 0x80_u8 >> bit;
@@ -124,6 +124,10 @@ impl BitVec {
         }
     }
 
+    pub fn overall_capacity_at_least(&mut self, bits: u64) {
+        self.ensure_vec_large_enough(bits);
+    }
+
     pub fn bit_len(&self) -> u64 {
         self.1
     }