Adds sources parameter codes on Sources page

data-sources.md

@@ -4,6 +4,8 @@ Mapzen Search is powered by several major open data sets and owes a tremendous d
 
 ## OpenStreetMap
 
+`sources=openstreetmap` | `sources=osm`
+
 [OpenStreetMap](https://www.openstreetmap.org/) is a community-driven, editable map of the world. It prioritizes local knowledge and individual contributions over bulk imports, which often means it has excellent coverage even in remote areas where no large-scale mapping efforts have been attempted. OpenStreetMap contains information on landmarks, buildings, roads, and natural features.
 
 With its coverage of roads as well as rich metadata, OpenStreetMap is arguably the most valuable dataset used by Mapzen Search for general usage.
@@ -12,6 +14,8 @@ All OpenStreetMap data is licensed under the [ODbL](http://opendatacommons.org/l
 
 ## Quattroshapes
 
+`sources=quattroshapes` | `sources=qs`
+
 [Quattroshapes](http://quattroshapes.com/) provides global coverage of location data for:
 
 - countries
@@ -28,6 +32,8 @@ Quattroshapes data is licensed [CC BY](http://creativecommons.org/licenses/by/2.
 
 ## OpenAddresses
 
+`sources=openaddresses` | `sources=osm`
+
 [OpenAddresses](http://openaddresses.io/) is a collection of authoritatively sourced data for addresses around the world, with over 200 million addresses. Data in OpenAddresses only comes from national, state, and local governments, so this data is highly authoritative. Because it consists of entirely bulk imports, OpenAddresses is a large, global, and rapidly growing dataset. Many countries, particularly in Europe, now have every address represented in OpenAddresses.
 
 OpenAddresses is by far the largest dataset by number of records used by Mapzen Search, so even though it only contains address data (as in no building names or other metadata), it's a great resource for global geocoding.
@@ -36,6 +42,8 @@ As OpenAddresses is sourced from regional governments, its data is in the public
 
 ## Geonames
 
+`sources=geonames` | `sources=gn`
+
 [Geonames](http://www.geonames.org/) is an aggregation of many authoritative and non-authoritative datasets. It contains information on everything from country borders to airport names to geographical features. While Geonames does not contain any shape data (such as country borders), it does have a powerful and well defined hierarchy to describe the relationships between different records. This custom hierarchy makes it harder to use in combination with data from other sources, but the Mapzen [Who's On First](http://whosonfirst.mapzen.com/) project will help by providing concordance between Geonames and other datasets.
 
 In the meantime, Geonames still provides a wide variety of useful data that helps augment the other datasets used by Mapzen Search.