The information is stored in your computers memory (RAM) using something called "Hash Tables", you won't see the file "Links.dat" until mIRC has been closed as this is when it saves to the file, it may also be hidden by your version of Windows.
If you do a search for a "Hash Tables Editor" or even a viewer you will find a few that you can load into mIRC and will allow you to manually view/edit the data.
As far as a !editlink commnd is concerned, would you want just the person that added the link to be able to modify it?
