Add explanation about minimum should match and coordination factor

core/src/main/java/org/elasticsearch/common/lucene/search/Queries.java

@@ -117,6 +117,9 @@ public class Queries {
         if (minimumShouldMatch == null) {
             return query;
         }
+        // Queries with a single word expanded with synonyms 
+        // have their coordination factor disabled (@see org.apache.lucene.util.QueryBuilder#analyzeBoolean()).
+        // minimumShouldMatch should not be applicable in such case.
         if (query.isCoordDisabled()) {
             return query;
         }