Mention solana discord channel

Signed-off-by: Sean Young <sean@mess.org>

docs/index.rst

@@ -13,7 +13,8 @@ Using Solang, you can compile smart contracts written in
 Solang aims for source file compatibility with the Ethereum EVM Solidity compiler,
 version 0.7. Where differences exists, this is noted in the :ref:`language documentation <language>`.
 The repository can be found on `github <https://github.com/hyperledger-labs/solang>`_
-and we have a `channel on chat.hyperledger.org <https://chat.hyperledger.org/channel/solang>`_.
+and we have a `channel #solang on chat.hyperledger.org <https://chat.hyperledger.org/channel/solang>`_, and
+a `channel #solang-solidity-compiler on Solana Discord <https://discordapp.com/invite/pquxPsq>`_.
 
 .. toctree::
    :maxdepth: 3