Update docs

Author: chipshort

MIGRATING.md

@@ -30,8 +30,9 @@ major releases of `cosmwasm`. Note that you can also view the
   want to enable the `std` feature now, as we might move certain existing
   functionality to that feature in the future to support no_std environments:
 
-  ```toml
-  cosmwasm-std = { version = "2.0.0", default-features = false, features = ["std", ...] }
+  ```diff
+  -cosmwasm-std = { version = "2.0.0", default-features = false, features = [...] }
+  +cosmwasm-std = { version = "2.0.0", default-features = false, features = ["std", ...] }
   ```
 
 - `ContractInfoResponse::new` now takes all fields of the response as

docs/USING_COSMWASM_STD.md

@@ -74,7 +74,8 @@ there it becomes impossible to use the contract in chains with lower CosmWasm
 versions. If you add `abort`, it becomes impossible for the contract developer
 to opt out of the abort feature due to your library. Since this affects the
 default features `abort` and `iterator`, you should always disable default
-features.
+features. However, you should make sure to keep the `std` feature enabled, as we
+might move certain existing functionality to that feature in the future.
 
 Also libraries should define a loose version range that allows the contract
 developer to control which cosmwasm-std version they want to use in the final
@@ -85,5 +86,6 @@ A typical dependency then looks like this:
 
 ```toml
 # We really need `stargate` here as this is an IBC related library. `abort` and `iterator` are not needed.
-cosmwasm-std = { version = "1.0.1", default-features = false, features = ["stargate"] }
+# `std` should always stay enabled.
+cosmwasm-std = { version = "1.0.1", default-features = false, features = ["std", "stargate"] }
 ```