Migrate all examples to use tweaked.cc

Might as well, I've got the server capacity to spare. Hopefully.

doc/events/http_failure.md

@@ -16,7 +16,7 @@ This event is normally handled inside @{http.get} and @{http.post}, but it can s
 ## Example
 Prints an error why the website cannot be contacted:
 ```lua
-local myURL = "http://this.website.does.not.exist"
+local myURL = "https://does.not.exist.tweaked.cc"
 http.request(myURL)
 local event, url, err
 repeat

doc/events/websocket_closed.md

@@ -11,7 +11,7 @@ The @{websocket_closed} event is fired when an open WebSocket connection is clos
 ## Example
 Prints a message when a WebSocket is closed (this may take a minute):
 ```lua
-local myURL = "ws://echo.websocket.org"
+local myURL = "wss://example.tweaked.cc/echo"
 local ws = http.websocket(myURL)
 local event, url
 repeat

doc/events/websocket_failure.md

@@ -15,7 +15,7 @@ This event is normally handled inside @{http.websocket}, but it can still be see
 ## Example
 Prints an error why the website cannot be contacted:
 ```lua
-local myURL = "ws://this.website.does.not.exist"
+local myURL = "wss://example.tweaked.cc/not-a-websocket"
 http.websocketAsync(myURL)
 local event, url, err
 repeat

doc/events/websocket_message.md

@@ -14,7 +14,7 @@ This event is normally handled by @{http.Websocket.receive}, but it can also be
 ## Example
 Prints a message sent by a WebSocket:
 ```lua
-local myURL = "ws://echo.websocket.org"
+local myURL = "wss://example.tweaked.cc/echo"
 local ws = http.websocket(myURL)
 ws.send("Hello!")
 local event, url, message

doc/events/websocket_success.md

@@ -15,7 +15,7 @@ This event is normally handled inside @{http.websocket}, but it can still be see
 ## Example
 Prints the content of a website (this may fail if the request fails):
 ```lua
-local myURL = "ws://echo.websocket.org"
+local myURL = "wss://example.tweaked.cc/echo"
 http.websocketAsync(myURL)
 local event, url, handle
 repeat