Fix broken link to 'tiled coordinate reference system' in Key scenarios

Author: Malvoz

high-level-api.md

@@ -84,7 +84,7 @@ Locations are specified in coordinates of one of the coordinate systems associat
 
 <h5 id="the-input-type-location-units-attribute">The <code>units</code> attribute</h5>
 
-Dynamic Web maps are pannable, zoomable and queryable through user gestures.  As a map is manipulated, it may require new content to cover its extent, or to respond to a query. To get new content, location events are generated for the extent implicated in the event (or a part of the extent, such as a map tile). Locations associated with the events are referenced by location inputs, by virtue of the combination of input attributes.  The `units` attribute has a small set of possible values, which can be one of `tcrs`, `pcrs`, `gcrs`, `map`, `tilematrix` or `tile`.  Each of these values signifies the child coordinate system from the parent [tiled coordinate reference system](README.md#tiled-coordinate-reference-systems) in which the event is considered to take place.  If the author specifies `units="tilematrix"`, for example, the location input refers to the location of each required tile as it is required. 
+Dynamic Web maps are pannable, zoomable and queryable through user gestures.  As a map is manipulated, it may require new content to cover its extent, or to respond to a query. To get new content, location events are generated for the extent implicated in the event (or a part of the extent, such as a map tile). Locations associated with the events are referenced by location inputs, by virtue of the combination of input attributes.  The `units` attribute has a small set of possible values, which can be one of `tcrs`, `pcrs`, `gcrs`, `map`, `tilematrix` or `tile`.  Each of these values signifies the child coordinate system from the parent [tiled coordinate reference system](key-scenarios.md#tiled-coordinate-reference-systems) in which the event is considered to take place.  If the author specifies `units="tilematrix"`, for example, the location input refers to the location of each required tile as it is required. 
 
 <h5 id="the-input-type-location-axis-attribute">The <code>axis</code> attribute</h5>