Clarify context suggestions filtering and boosting

docs/reference/search/suggesters/context-suggest.asciidoc

@@ -13,6 +13,9 @@ Every context mapping has a unique name and a type. There are two types: `catego
 and `geo`. Context mappings are configured under the `contexts` parameter in
 the field mapping.
 
+NOTE: It is mandatory to provide a context when indexing and querying
+      a context enabled completion field.
+
 The following defines types, each with two context mappings for a completion
 field:
 
@@ -84,10 +87,6 @@ PUT place_path_category
 NOTE: Adding context mappings increases the index size for completion field. The completion index
 is entirely heap resident, you can monitor the completion field index size using <<indices-stats>>.
 
-NOTE: deprecated[7.0.0, Indexing a suggestion without context on a context enabled completion field is deprecated
-and will be removed in the next major release. If you want to index a suggestion that matches all contexts you should
-add a special context for it.]
-
 [[suggester-context-category]]
 [float]
 ==== Category Context
@@ -160,9 +159,9 @@ POST place/_search?pretty
 // CONSOLE
 // TEST[continued]
 
-Note: deprecated[7.0.0, When no categories are provided at query-time, all indexed documents are considered.
-Querying with no categories on a category enabled completion field is deprecated and will be removed in the next major release
-as it degrades search performance considerably.]
+NOTE: If multiple categories or category contexts are set on the query
+they are merged as a disjunction. This means that suggestions match
+if they contain at least one of the provided context values.
 
 Suggestions with certain categories can be boosted higher than others.
 The following filters suggestions by categories and additionally boosts
@@ -218,6 +217,9 @@ multiple category context clauses. The following parameters are supported for a
     so on, by specifying a category prefix of 'type'.
     Defaults to `false`
 
+NOTE: If a suggestion entry matches multiple contexts the final score is computed as the
+maximum score produced by any matching contexts.
+
 [[suggester-context-geo]]
 [float]
 ==== Geo location Context
@@ -307,6 +309,10 @@ POST place/_search
 NOTE: When a location with a lower precision at query time is specified, all suggestions
 that fall within the area will be considered.
 
+NOTE: If multiple categories or category contexts are set on the query
+they are merged as a disjunction. This means that suggestions match
+if they contain at least one of the provided context values.
+
 Suggestions that are within an area represented by a geohash can also be boosted higher
 than others, as shown by the following:
 
@@ -349,6 +355,9 @@ POST place/_search?pretty
     that fall under the geohash representation of '(43.6624803, -79.3863353)'
     with a default precision of '6' by a factor of `2`
 
+NOTE: If a suggestion entry matches multiple contexts the final score is computed as the
+maximum score produced by any matching contexts.
+
 In addition to accepting context values, a context query can be composed of
 multiple context clauses. The following parameters are supported for a
 `category` context clause:

server/src/test/java/org/elasticsearch/search/suggest/ContextCompletionSuggestSearchIT.java

@@ -275,7 +275,6 @@ public void testMultiContextFiltering() throws Exception {
         assertSuggestions("foo", typeFilterSuggest, "suggestion9", "suggestion6", "suggestion5", "suggestion2", "suggestion1");
     }
 
-    @AwaitsFix(bugUrl = "multiple context boosting is broken, as a suggestion, contexts pair is treated as (num(context) entries)")
     public void testMultiContextBoosting() throws Exception {
         LinkedHashMap<String, ContextMapping<?>> map = new LinkedHashMap<>();
         map.put("cat", ContextBuilder.category("cat").field("cat").build());
@@ -328,7 +327,8 @@ public void testMultiContextBoosting() throws Exception {
             CategoryQueryContext.builder().setCategory("cat1").build())
         );
         multiContextBoostSuggest.contexts(contextMap);
-        assertSuggestions("foo", multiContextBoostSuggest, "suggestion9", "suggestion6", "suggestion5", "suggestion2", "suggestion1");
+        // the score of each suggestion is the maximum score among the matching contexts
+        assertSuggestions("foo", multiContextBoostSuggest, "suggestion9", "suggestion8", "suggestion5", "suggestion6", "suggestion4");
     }
 
     public void testSeveralContexts() throws Exception {