DC - Silver line now alternates to Largo and New Carrollton

[si404]

Per the map: https://www.wmata.com/schedules/maps/wmata-system-map.cfm

Also they have now moved to single letter bullets (R) (O) (Y) (G) (B) (S), so there might be possible line name changes from colours explicitly said to letters (while DC doesn't have the bilingual issue that LA has that moved their coloured lines to lettered ones, it does seem to be a cool thing to do at the moment with Chicago's Metra and SEPTA also moving from named routes to alphanumeric designations) in the future.

[Duke87]

https://github.com/TravelMapping/RailwayData/pull/306 forks the Silver Line. Side note, this is a case where it would be nice to be able to include one wpt file in two connected routes, as the two are identical in Virginia. Alas, the system does not support that, so a duplicate wpt file for the Virginia portion had to be created in order to allow both branches to have a full connected route.

As for the route bullets moving to one letter instead of two... no, this isn't a material rebrand. The Silver Line is still the Silver Line and I don't think even WMATA is trying to say otherwise. But as no two line colors begin with the same letter, two letter abbreviations weren't necessary.

[cl94]

Yeah, I'm with Duke here. The full color name is still the official name of the line, and that is what we are using on the site. No changes necessary.