[Docs] Fix reference to `boost` and `slop` params (#42803)

For `multi_match` query: link `boost` param to the generic reference
for query usage and `slop` to the `match_phrase` query where its usage
is documented.

Fixes: #40091

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

@@ -290,9 +290,9 @@ GET /_search
 --------------------------------------------------
 // CONSOLE
 
-Also, accepts `analyzer`, `boost`, `lenient`, `slop` and `zero_terms_query`  as explained
-in <<query-dsl-match-query>>.  Type `phrase_prefix` additionally accepts
-`max_expansions`.
+Also, accepts `analyzer`, <<mapping-boost,`boost`>>, `lenient` and `zero_terms_query` as explained
+in <<query-dsl-match-query>>, as well as `slop` which is explained in <<query-dsl-match-query-phrase>>.
+Type `phrase_prefix` additionally accepts `max_expansions`.
 
 [IMPORTANT]
 [[phrase-fuzziness]]