Fix typo (paritytech#12900)

Author: ltfschoen

README.md

@@ -12,7 +12,7 @@ Then try out one of the [tutorials](https://docs.substrate.io/tutorials/).
 
 ## Community & Support
 
-Join the highly active and supportive community on the [Susbstrate Stack Exchange](https://substrate.stackexchange.com/) to ask questions about use and problems you run into using this software.
+Join the highly active and supportive community on the [Substrate Stack Exchange](https://substrate.stackexchange.com/) to ask questions about use and problems you run into using this software.
 Please do report bugs and [issues here](https://github.com/paritytech/substrate/issues) for anything you suspect requires action in the source. 
 
 ## Contributions & Code of Conduct