update docs to reflect new URL for string objects

doc/apiv3-documentation.apib

@@ -1886,14 +1886,14 @@ This is an example of how a schema might look like. Note that this endpoint does
 String objects are a linkable representation of strings. They merely serve the purpose of making links to strings possible,
 e.g. to be able to provide `allowedValues` for a string typed property.
 
-## String Object [/api/v3/string_objects/{value}]
+## String Object [/api/v3/string_objects?value={value}]
 
 + Model
     + Body
 
             {
                 "_links": {
-                    "self": { "href": "/api/v3/string_objects/Foo" }
+                    "self": { "href": "/api/v3/string_objects?value=Foo" }
                 },
                 "_type": "StringObject",
                 "value": "Foo"