[DOCS] Adds the evaluate API endpoint base to the quick reference page. (#439)

This PR adds the evaluate API endpoint base to the API quick reference page.

Author: szabosteve

docs/en/stack/ml/df-analytics/api-quickref.asciidoc

@@ -2,15 +2,21 @@
 [[ml-dfanalytics-apis]]
 == API quick reference
 
-With the exception of the evaluation API, all {dfanalytics} endpoints have the
-following base:
+All {dfanalytics} endpoints have the following base:
 
 [source,js]
 ----
 /_ml/data_frame/analytics
 ----
 // NOTCONSOLE
 
+The evaluation API endpoint has the following base:
+
+[source,js]
+----
+/_ml/data_frame/_evaluate
+----
+// NOTCONSOLE
 
 * {ref}/put-dfanalytics.html[Create {dfanalytics-jobs}]
 * {ref}/delete-dfanalytics.html[Delete {dfanalytics-jobs}]