Update Readmes (#298)

* Clarify substrate/ink! interaction in Readme

* Update delegator instructions

* Apply suggestions from code review

Co-Authored-By: Hero Bird <robin.freyler@gmail.com>

README.md

@@ -31,6 +31,15 @@ For more information please visit [the ink! tutorial](https://substrate.dev/subs
 | ------------- | ------------- | ------------- |
 | [![][h1]][h2] | [![][f1]][f2] | [![][g1]][g2] |
 
+### Interaction with Substrate
+
+Susbtrate contains the `frame-contracts` module, which provides a generic
+smart contract interface for Wasm blobs. It takes care of e.g. state rent,
+storage, costs, etc..
+
+ink! is a smart contract language which targets the interface exposed by
+`frame-contracts`. As such, ink! smart contracts are compiled to Wasm.
+
 ### Scripts
 
 Use the scripts provided under `scripts` directory in order to run checks on either the workspace or all examples. Please do this before pushing work in a PR.

examples/lang/delegator/README.md

@@ -13,8 +13,8 @@ In order to test this bundle of smart contracts you need to do the following:
 
 1. Compile all dependencies of the Delegator smart contract using the `./build-all.sh` script.
    As usual you will receive their respective Wasm blobs in their respective `target` folders.
-1. Go to the delegator directory (root of the example) and run `cargo run -p abi-gen` in order
-   to generate the ABI file for the Delegator smart contract.
+1. Go to the delegator directory (root of the example) and run `cargo contract generate-metadata`
+   in order to generate the ABI file for the Delegator smart contract.
    Note: You won't need an ABI file for the other smart contracts since we won't operate on them
          using the Polkadot UI.
 1. Put the Wasm blobs of Accumulator, Adder, Subber and the Delegator on the chain via `put_code` command.

examples/lang2/delegator/README.md

@@ -13,8 +13,8 @@ In order to test this bundle of smart contracts you need to do the following:
 
 1. Compile all dependencies of the Delegator smart contract using the `./build-all.sh` script.
    As usual you will receive their respective Wasm blobs in their respective `target` folders.
-1. Go to the delegator directory (root of the example) and run `cargo run -p abi-gen` in order
-   to generate the ABI file for the Delegator smart contract.
+1. Go to the delegator directory (root of the example) and run `cargo contract generate-metadata`
+   in order to generate the ABI file for the Delegator smart contract.
    Note: You won't need an ABI file for the other smart contracts since we won't operate on them
          using the Polkadot UI.
 1. Put the Wasm blobs of Accumulator, Adder, Subber and the Delegator on the chain via `put_code` command.