[DOCS] Clarify scoring for multi_match phrase type (#32672)

The original statement "Runs a match_phrase query on each field and combines the _score from each field." for the phrase type is a but misleading. The phrase type behaves like the best_fields type and does not combine the scores of each fields.

docs/reference/query-dsl/multi-match-query.asciidoc

@@ -83,8 +83,8 @@ parameter, which can be set to:
                     were one big field. Looks for each word in *any*
                     field. See <<type-cross-fields>>.
 
-`phrase`::          Runs a `match_phrase` query on each field and combines
-                    the `_score` from each field.  See <<type-phrase>>.
+`phrase`::          Runs a `match_phrase` query on each field and uses the  `_score` 
+                    from the best field.  See <<type-phrase>>.
 
 `phrase_prefix`::   Runs a `match_phrase_prefix` query on each field and
                     combines the `_score` from each field.  See <<type-phrase>>.