Update wit/proxy.wit

Co-authored-by: Luke Wagner <mail@lukewagner.name>

wit/proxy.wit

@@ -5,7 +5,7 @@ package wasi:http;
 /// this world may concurrently stream in and out any number of incoming and
 /// outgoing HTTP requests.
 world proxy {
-  // HTTP proxies have access to time and randomness.
+  /// HTTP proxies have access to time and randomness.
   include wasi:clocks/imports;
   import wasi:random/random;