FIP-0048: fix - remove repeated words (#1023)

FIPS/fip-0048.md

@@ -32,7 +32,7 @@ This will allow users to:
 ## Abstract
 <!--A short (~200 word) description of the technical issue being addressed.-->
 
-Currently, adding new address types and address derivation methods to the Filecoin network requires extensive changes and a network upgrade. This FIP introduces a new user-extensible address class such that new addressing systems can be added by _users_ without extensive changes and network upgrades network upgrades.
+Currently, adding new address types and address derivation methods to the Filecoin network requires extensive changes and a network upgrade. This FIP introduces a new user-extensible address class such that new addressing systems can be added by _users_ without extensive changes and network upgrades.
 
 It achieves this by adding a new address class (`f4`) where user-definable "address management" actors will be able to create new actors under an address-manager specific `f4` prefix (specifically, `f4{address-manager-actor-id}f`). This will allow Filecoin to support the native addressing schemes of foreign runtimes like the EVM and create new _predictable_ addressing scheme to support interactions (both actually and counterfactually) with addresses that do not yet exist on-chain.