adding ext pause comment

Author: sbvegan

pages/stack/smart-contracts.mdx

@@ -279,19 +279,20 @@ and most importantly making the stack modular.
 
 #### AddressManager 
 
-AddressManager is a legacy contract that was used in the old version of the 
+`AddressManager` is a legacy contract that was used in the old version of the 
 Optimism system to manage a registry of string names to addresses. We now use a
 more standard proxy system for most contracts, but this contract is still used for
 the L1CrossDomainMessenger, via ResolvedDelegateProxy
 
 #### SuperchainConfig
 
-The SuperchainConfig contract is used to manage configuration of global 
-superchain values.
+The `SuperchainConfig` contract is used to manage configuration of global 
+superchain values. It has the ability to pause and unpause all withdrawals
+in the Superchain.
 
 #### L1CrossDomainMessenger
 
-The L1CrossDomainMessenger is a message passing interface between L1 and L2
+The `L1CrossDomainMessenger` is a message passing interface between L1 and L2
 responsible for sending and receiving data on the L1 side. Users are encouraged
 to use this interface instead of interacting with lower-level contracts directly.