What is the argument name specification (for)?

Resharper suggested that I add the argument name specs changing the method call:

MyEvent(sender, e);   

      

        
        
        
      

    

to

MyEvent(sender: sender, e: e); 

      

        
        
        
      

    

Never seen this syntax before and couldn't googling what the specs of the argument name are and why are they needed?

PS
There is a similar discussion:

• Should these arguments be added or removed?

but he didn't touch on my question