Service documentation updates

[kjacobsen16]

From Christine D. from ESRI:

• [ ] Typo

• [ ] "Also to delineate, we need to pass X, Y and the state/study area. I know there may be multiple areas under one point but it may be helpful to let the user know what those are." - I asked Pete, and sounds like we should just add a list of all accepted regions to the documentation

[amedenblik]

~Closed in favor of https://github.com/USGS-WiM/StreamStatsWebserviceDocumentation/issues/99~ Never mind, apparently the issues are connected.