Make http.websocket call synchronous in bios.lua

I thought I'd done this already, but it's possible it got lost during a
rebase.

src/main/resources/assets/computercraft/lua/bios.lua

@@ -737,6 +737,28 @@ if http then
             if url == _url then return ok, err end
         end
     end
+
+    local nativeWebsocket = http.websocket
+    http.websocketAsync = nativeWebsocket
+    http.websocket = function( _url, _headers )
+        if type( _url ) ~= "string" then
+            error( "bad argument #1 (expected string, got " .. type( _url ) .. ")", 2 )
+        end
+        if _headers ~= nil and type( _headers ) ~= "table" then
+            error( "bad argument #2 (expected table, got " .. type( _headers ) .. ")", 2 )
+        end
+        local ok, err = nativeWebsocket( _url, _headers )
+        if not ok then return ok, err end
+
+        while true do
+            local event, url, param = os.pullEvent( )
+            if event == "websocket_success" and url == _url then
+                return param
+            elseif event == "websocket_failure" and url == _url then
+                return false, param
+            end
+        end
+    end
 end
 
 -- Install the lua part of the FS api