Multiword Synonym Search broken

[Schabernack]

I am not sure if this can actually be considered a bug, here it goes anyway:

If you use pgsql thesaurus to define multi-word synonyms, they will not get picked up by searchable. If you search for multiple words, searchable will 'and' them together. This means that every word is lexed separately, synonyms are not picked up:

=> select * from test where search_vector @@ to_tsquery('pg', 'synonym & test');
(No rows)
=> select to_tsquery('synonym & test');
     to_tsquery
--------------------
 'synonym' & 'test'
(1 row)

what should be done instead is to use plainto_tsquery or escape the string properly:

=> select to_tsquery('''synonym  test''');
 to_tsquery
------------
 'result synonym word'
(1 row)
=> select * from test where search_vector @@ to_tsquery('pg', '''synonym  test''');
-[ RECORD 1 ]---+----------

Thats obviously not something that should be done for every search, but a fallback option could be useful for this usecase.