Update README.md

Author: samdotola

README.md

@@ -190,7 +190,7 @@ extern "C" fn ibc_packet_ack(env_ptr: u32, msg_ptr: u32) -> u32;
 extern "C" fn ibc_packet_timeout(env_ptr: u32, msg_ptr: u32) -> u32;
 ```
 
-`allocate`/`deallocate` allow the host to manage data within the Wasm VM. If
+`allocate` and `deallocate` allow the host to manage data within the Wasm VM. If
 you're using Rust, you can implement them by simply
 [re-exporting them from cosmwasm::exports](https://github.com/CosmWasm/cosmwasm/blob/v0.6.3/contracts/hackatom/src/lib.rs#L5).
 `instantiate`, `execute` and `query` must be defined by your contract.