book: remove sanchonet

Author: johnalotoski

mdbook/SUMMARY.md

@@ -5,7 +5,6 @@
 # Reference
 
 - [Environments](environments.md)
-  - [Sanchonet](env-sanchonet.md)
   - [Preview](env-preview.md)
   - [Pre-production](env-preprod.md)
   - [Mainnet](env-mainnet.md)

mdbook/env-sanchonet.md

@@ -4,7 +4,6 @@ The official Cardano Environment configuration files.
 
 Environment description and configuration files available are:
 
-- [Sanchonet Testnet](env-sanchonet.html)
 - [Preview Testnet](env-preview.html)
 - [Pre-production Testnet](env-preprod.html)
 - [Production (Mainnet)](env-mainnet.html)