Substreams-powered subgraphs updates (#446)

* streamline example setup, add note on supported networks

* link out to more examples

* code styling for consistency

Co-authored-by: Benoît Rouleau <benoit.rouleau@icloud.com>

---------

Co-authored-by: Benoît Rouleau <benoit.rouleau@icloud.com>

Author: azf20

website/pages/en/cookbook/substreams-powered-subgraphs.mdx

@@ -4,15 +4,25 @@ title: Substreams-powered subgraphs
 
 [Substreams](/substreams/README) is a new framework for processing blockchain data, developed by StreamingFast for The Graph Network. A substreams modules can output entity changes, which are compatible with Subgraph entities. A subgraph can use such a Substreams module as a data source, bringing the indexing speed and additional data of Substreams to subgraph developers.
 
-> This cookbook uses this [Substreams-powered subgraph as a reference](https://github.com/graphprotocol/graph-tooling/tree/main/examples/substreams-powered-subgraph).
-
 ## Requirements
 
-This cookbook requires [yarn](https://yarnpkg.com/) as well as [the dependencies necessary for local Substreams development](https://substreams.streamingfast.io/developers-guide/installation-requirements).
+This cookbook requires [yarn](https://yarnpkg.com/), [the dependencies necessary for local Substreams development](https://substreams.streamingfast.io/developers-guide/installation-requirements), and the latest version of Graph CLI (>=0.52.0):
+
+```
+npm install -g @graphprotocol/graph-cli
+```
+
+## Get the cookbook
+
+> This cookbook uses this [Substreams-powered subgraph as a reference](https://github.com/graphprotocol/graph-tooling/tree/main/examples/substreams-powered-subgraph).
+
+```
+graph init --from-example substreams-powered-subgraph
+```
 
 ## Defining a Substreams package
 
-A Substreams package is composed of types (defined as [Protocol Buffers](https://protobuf.dev/)), modules (written in Rust), and a `substreams.yaml` file which references the types, and specifies how modules are triggered. [Learn more about Substreams development](/substreams/README).
+A Substreams package is composed of types (defined as [Protocol Buffers](https://protobuf.dev/)), modules (written in Rust), and a `substreams.yaml` file which references the types, and specifies how modules are triggered. [Visit the Substreams documentation to learn more about Substreams development](/substreams/README), and check out [awesome-substreams](https://github.com/pinax-network/awesome-substreams) and the [Substreams cookbook](https://github.com/pinax-network/substreams-cookbook) for more examples.
 
 The Substreams package in question detects contract deployments on Mainnet Ethereum, tracking the creation block and timestamp for all newly deployed contracts. To do this, there is a dedicated `Contract` type in `/proto/example.proto` ([learn more about defining Protocol Buffers](https://protobuf.dev/programming-guides/proto3/#simple)):
 
@@ -145,7 +155,11 @@ This generates a `spkg` file based on the package name and version from `substre
 
 ## Defining a Substreams-powered subgraph
 
-Substreams-powered subgraphs introduce a new `kind` of data source, "substreams". Such subgraphs can only have one data source. This data source must specify the Substreams network, the Substreams package (`spkg`) as a relative file location, and the module within that Substreams package which produces subgraph-compatible entity changes (in this case `map_entity_changes`, from the Substreams package above). The mapping is specified, but simply identifies the mapping kind ("substreams/graph-entities") and the apiVersion.
+Substreams-powered subgraphs introduce a new `kind` of data source, "substreams". Such subgraphs can only have one data source.
+
+This data source must specify the indexed network, the Substreams package (`spkg`) as a relative file location, and the module within that Substreams package which produces subgraph-compatible entity changes (in this case `map_entity_changes`, from the Substreams package above). The mapping is specified, but simply identifies the mapping kind ("substreams/graph-entities") and the apiVersion.
+
+> Currently the Subgraph Studio and The Graph Network support Substreams-powered subgraphs which index `mainnet` (Mainnet Ethereum).
 
 ```yaml
 specVersion: 0.0.4

website/pages/en/developing/supported-networks.mdx

@@ -31,13 +31,13 @@ import { getSupportedNetworks } from '@/src/getSupportedNetworks'
 
 The hosted service relies on the stability and reliability of the underlying technologies, namely the provided JSON RPC endpoints.
 
-You will **not be able** to publish a subgraph that indexes a non-mainnet network to the decentralized Graph Network in [Subgraph Studio](/deploying/subgraph-studio).
-
 Ropsten, Rinkeby and Kovan are being deprecated. Read more on the [Ethereum Foundation Blog](https://blog.ethereum.org/2022/06/21/testnet-deprecation). As of Feb 25th 2023, Ropsten, Rinkeby and Kovan are no longer supported by the Hosted Service. Goerli will be maintained by client developers post-merge, and is also supported by the Hosted Service. Developers who currently use Ropsten, Rinkeby or Kovan as their staging/testing environment are encouraged to migrate to Goerli.
 
 Subgraphs indexing Gnosis Chain can now be deployed with the `gnosis` network identifier. `xdai` is still supported for existing hosted service subgraphs.
 
-For a full list of which features are supported on the decentralized network, see [this page](https://github.com/graphprotocol/indexer/blob/main/docs/networks/mainnet.md#feature-support).
+For a full list of which features are supported on the decentralized network, see [this page](https://github.com/graphprotocol/indexer/blob/main/docs/feature-support-matrix.md).
+
+Substreams-powered subgraphs indexing `mainnet` Ethereum are supported on the Subgraph Studio and decentralized network.
 
 ## Graph Node