Semantic fix for easy interpretation

Author: Emilia Hane

discv5/discv5-theory.md

@@ -428,8 +428,8 @@ listen socket. If those sockets are not equivalent, the node is behind NAT and t
 [mechanism for keeping holes punched] is activated. Like so, a node assumes it is behind
 NAT if an externally reachable socket is omitted from the initial configuration and must
 activate the [mechanism for keeping holes punched]. [Runtime address discovery] asses the
-external socket used by the local node. Once a new externally reachable IP address is known,
-implementations will try to bind to the address at some number of randomly selected ports
+external socket used by the local node. Once a new externally reachable socket is known,
+implementations will try to bind to its IP address at some number of randomly selected ports
 from a given range of probably unused ports. If binding succeeds with any port, the node is
 not behind NAT and the [mechanism for keeping holes punched] is deactivated. This solution
 assumes, in most scenarios where port-forwarding cannot be configured the local node host's