clarify optimism

Author: cryptofreedman

docs/reference/tables/available-chains.md

@@ -53,7 +53,7 @@ Polygon follows all the rules of ETH mainnet and querying on Dune works exactly
     ![optimism icon](../images/optimism-icon.png)
 
 !!! warning
-    Due to an error with our Node provider, we're missing about 235k Optimisim blocks with no current timeline for a fix. [See the list of the exact missing blocks here](optimism-missing-blocks.csv).
+    Due to an error with the current version of the Optimism client, we're missing about 235k Optimism blocks with no current timeline for a fix. [See the list of the exact missing blocks here](optimism-missing-blocks.csv).
 
 Optimism is a Layer 2 Optimistic Rollup network designed to utilize the strong security guarantees of Ethereum while reducing its cost and latency. Optimism processes transactions outside of Ethereum Mainnet, reducing congestion on the base layer and improving scalability. For a Deep Dive into Optimism, we recommend reading through their [Documentation](https://community.optimism.io/docs/how-optimism-works).