SD: I-90/SD 258 NMP @ Plankinton

[mapcat]

I-90's 308 point doesn't match up with the I-90_W point on SD 258. Looks like SD 258's point is centered on the interchange, so using those coordinates would fix it. Also, since 258 only intersects I-90 one time, changing I-90_W to just I-90 would be appropriate.

[Markkos1992]

https://github.com/TravelMapping/HighwayData/pull/6005