replace `NewLine` func with `NewWeightedLine` for WeightedUndirectedG…
Created by: highway900
…raph type. This appears to be the correct functionality
Correct me if I am wrong but WeightedUndirectedGraph
should have NewWeightedLine
functionality as opposed to NewLine
The current behavior makes it non-trivial to add a weight to a line using NewLine
This PR obviously needs some tests, but I just wanted to check I wasn't missing something obvious in regards to the functionality
Cheers
-Matt