codecs: rename MakeCodecs rename and docs update (#8245)

* codecs: rename MakeCodecs to MakeTestCodecs

* update changelog

* remove MakeTestCodecs

* typo

docs/basics/app-anatomy.md

@@ -113,17 +113,19 @@ The `EncodingConfig` structure is the last important part of the `app.go` file.
 
 Here are descriptions of what each of the four fields means:
 
-- `InterfaceRegistry`: The `InterfaceRegistry` is used by the Protobuf codec to handle interfaces, which are encoded and decoded (we also say "unpacked") using [`google.protobuf.Any`](https://github.com/protocolbuffers/protobuf/blob/master/src/google/protobuf/any.proto). `Any` could be thought as a struct which contains a `type_url` (the concrete type of the interface) and a `value` (its encoded bytes). `InterfaceRegistry` provides a mechanism for registering interfaces and implementations that can be safely unpacked from `Any`. Each of the application's modules implements the `RegisterInterfaces` method, which can be used to register the module's own interfaces and implementations.
+- `InterfaceRegistry`: The `InterfaceRegistry` is used by the Protobuf codec to handle interfaces, which are encoded and decoded (we also say "unpacked") using [`google.protobuf.Any`](https://github.com/protocolbuffers/protobuf/blob/master/src/google/protobuf/any.proto). `Any` could be thought as a struct which contains a `type_url` (name of a concrete type implementing the interface) and a `value` (its encoded bytes). `InterfaceRegistry` provides a mechanism for registering interfaces and implementations that can be safely unpacked from `Any`. Each of the application's modules implements the `RegisterInterfaces` method, which can be used to register the module's own interfaces and implementations.
+  - You can read more about Any in [ADR-19](https://github.com/cosmos/cosmos-sdk/blob/master/docs/architecture/adr-019-protobuf-state-encoding.md#usage-of-any-to-encode-interfaces).
   - To go more into details, the SDK uses an implementation of the Protobuf specification called [`gogoprotobuf`](https://github.com/gogo/protobuf). By default, the [gogo protobuf implementation of `Any`](https://godoc.org/github.com/gogo/protobuf/types) uses [global type registration](https://github.com/gogo/protobuf/blob/master/proto/properties.go#L540) to decode values packed in `Any` into concrete Go types. This introduces a vulnerability where any malicious module in the dependency tree could registry a type with the global protobuf registry and cause it to be loaded and unmarshaled by a transaction that referenced it in the `type_url` field. For more information, please refer to [ADR-019](../architecture/adr-019-protobuf-state-encoding.md).
-- `Marshaler`: The `Marshaler` is the default codec used throughout the SDK. It is composed of a `BinaryMarshaler` used to encode and decode state, and a `JSONMarshaler` used to output data to the users (for example in the [CLI](#cli)). By default, the SDK uses Protobuf as `Marshaler`.
+- `Marshaler`: the default codec used throughout the SDK. It is composed of a `BinaryMarshaler` used to encode and decode state, and a `JSONMarshaler` used to output data to the users (for example in the [CLI](#cli)). By default, the SDK uses Protobuf as `Marshaler`.
 - `TxConfig`: `TxConfig` defines an interface a client can utilize to generate an application-defined concrete transaction type. Currently, the SDK handles two transaction types: `SIGN_MODE_DIRECT` (which uses Protobuf binary as over-the-wire encoding) and `SIGN_MODE_LEGACY_AMINO_JSON` (which depends on Amino). Read more about transactions [here](../core/transactions.md).
 - `Amino`: Some legacy parts of the SDK still use Amino for backwards-compatibility. Each module exposes a `RegisterLegacyAmino` method to register the module's specific types within Amino. This `Amino` codec should not be used by app developers anymore, and will be removed in future releases.
 
-The SDK exposes a `MakeCodecs` function used to create a `EncodingConfig`. It uses Protobuf as default `Marshaler`, and passes it down to the app's `appCodec` field. It also instantiates a legacy `Amino` codec inside the app's `legacyAmino` field.
+The SDK exposes a `MakeTestEncodingConfig` function used to create a `EncodingConfig` for the app  constructor (`NewApp`). It uses Protobuf as a default `Marshaler`.
+NOTE: this function is marked deprecated and should only be used to create an app or in tests. We are working on refactoring codec management in a post Stargate release.
 
-See an example of a `MakeCodecs` from `simapp`:
+See an example of a `MakeTestEncodingConfig` from `simapp`:
 
-+++ https://github.com/cosmos/cosmos-sdk/blob/v0.40.0-rc3/simapp/app.go#L429-L435
++++ https://github.com/cosmos/cosmos-sdk/blob/v0.40.0-rc3/simapp/simd/cmd/root.go#L179-196
 
 ## Modules