Unfortunately, it is not possible to do exactly what you suggested.
- We can't make links with a text that differs from the link URL. Messenger is responsible for making links clickable and it would be a serious concern when people could send links with a different text. Malicious users could send links which look like they're safe but will actually send you to a very nasty place.
- If we were to replace the incoming message by the plain URL, this replacing URL can't be longer than the original text (@warmth or #twiteq) because Messenger has already allocated the buffer to fit the message in - see notes in OnEvent_ChatWndReceiveMessage. Chances are very rare that you could make a URL which is shorter than the original text, even with some kind of URL shortening applied.
Therefore if anyone were to make such a script, it'd probably just pop up a toast or something to send you to the mentioned profile or search page, or the user would have to type in a command or click in a script window or whatever to access the webpage.
As you can see, when it comes to interacting with the chat history, Plus! scripting simply isn't powerful enough (...yet???).
/ 
