Fixing link and name (#481)

Author: MichaelMacaulay

website/pages/en/graphcast.mdx

@@ -10,7 +10,7 @@ Currently, the cost to broadcast information to other network participants is de
 
 The Graphcast SDK (Software Development Kit) allows developers to build Radios, which are gossip-powered applications that Indexers can run to serve a given purpose. We also intend to create a few Radios (or provide support to other developers/teams that wish to build Radios) for the following use cases:
 
-- Real-time cross-checking of subgraph data integrity ([POI Radio](https://docs.graphops.xyz/graphcast/radios/poi-radio)).
+- Real-time cross-checking of subgraph data integrity ([Subgraph Radio](https://docs.graphops.xyz/graphcast/radios/subgraph-radio)).
 - Conducting auctions and coordination for warp syncing subgraphs, substreams, and Firehose data from other Indexers.
 - Self-reporting on active query analytics, including subgraph request volumes, fee volumes, etc.
 - Self-reporting on indexing analytics, including subgraph indexing time, handler gas costs, indexing errors encountered, etc.