added docs to short_fastest graphhopper#747

Author: karussell

docs/web/api-doc.md

@@ -43,7 +43,7 @@ Unlock certain flexible features via `ch.disable=true` or disable CH on the serv
 Parameter        | Default    | Description
 :----------------|:-----------|:-----------
 ch.disable       | `false`    | Use this parameter in combination with one or more parameters of this table
-weighting        | `fastest`  | Which kind of 'best' route calculation you need. Other option is `shortest` (e.g. for foot and bike) and `curvature` (only for motorcycle)
+weighting        | `fastest`  | Which kind of 'best' route calculation you need. Other option is `shortest` (e.g. for `vehicle=foot` or `bike`), `short_fastest` if time and distance is expensive (e.g. for `vehicle=truck`) and `curvature` (only for `vehicle=motorcycle`)
 edge_traversal   |`false`     | Use `true` if you want to consider turn restrictions for bike and motor vehicles. Keep in mind that the response time is roughly 2 times slower.
 algorithm        |`dijkstrabi`| The algorithm to calculate the route. Other options are `dijkstra`, `astar`, `astarbi`, `alternative_route` and `round_trip`
 heading          | NaN        | Favour a heading direction for a certain point. Specify either one heading for the start point or as many as there are points. In this case headings are associated by their order to the specific points. Headings are given as north based clockwise angle between 0 and 360 degree. This parameter also influences the tour generated with `algorithm=round_trip` and force the initial direction.