net/http: make docs refer to Context.Value as a getter instead of context.WithValue

The doc comments of both ServerContextKey and LocalAddrContextKey both suggest that context.WithValue can be used to access (get) properties of the server or connection. This PR fixes those comments to refer to Context.Value instead.

Change-Id: I4ed383ef97ba1951f90c555243007469cfc18d4d
GitHub-Last-Rev: 05bc3acf82322e3dc77abc7fa0412efe01a77eac
GitHub-Pull-Request: golang/go#33833
Reviewed-on: https://go-review.googlesource.com/c/go/+/191838Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>

src/net/http/server.go

@@ -231,13 +231,13 @@ type CloseNotifier interface {
 
 var (
 	// ServerContextKey is a context key. It can be used in HTTP
-	// handlers with context.WithValue to access the server that
+	// handlers with Context.Value to access the server that
 	// started the handler. The associated value will be of
 	// type *Server.
 	ServerContextKey = &contextKey{"http-server"}
 
 	// LocalAddrContextKey is a context key. It can be used in
-	// HTTP handlers with context.WithValue to access the local
+	// HTTP handlers with Context.Value to access the local
 	// address the connection arrived on.
 	// The associated value will be of type net.Addr.
 	LocalAddrContextKey = &contextKey{"local-addr"}