Add new developer tool [Fixes #9318]

Completing the updates suggested in #9318

Author: alex-pakalniskis

src/content/developers/docs/programming-languages/rust/index.md

@@ -55,6 +55,7 @@ Need a more basic primer first? Check out [ethereum.org/learn](/learn/) or [ethe
 - [Foundry](https://github.com/gakonst/foundry)- _Toolkit for Ethereum application development_
 - [Ethers_rs](https://github.com/gakonst/ethers-rs)- _Ethereum library and wallet implementation_
 - [SewUp](https://github.com/second-state/SewUp) - _A library to help you build your Ethereum webassembly contract with Rust and just like develop in a common backend_
+- [Substreams](https://github.com/streamingfast/substreams) - _Parallelized blockchain data indexing technology_
 
 Looking for more resources? Check out [ethereum.org/developers.](/developers/)