Fix word_similarity() inconsistency in pg_trgm

When Who What
2018-03-21 12:00:20 Fedor Sigaev (sigaev) Closed in commitfest 2018-03 with status: Committed
2018-03-06 16:59:39 David Steele (dsteele) Added dsteele as reviewer
2018-02-07 15:21:21 David Steele (dsteele) Closed in commitfest 2018-01 with status: Moved to next CF
2017-12-18 12:45:56 Alexander Korotkov (smagen) New status: Needs review
2017-12-12 11:34:34 Fedor Sigaev (sigaev) New status: Waiting on Author
2017-12-12 11:23:01 Fedor Sigaev (sigaev) Changed reviewers to Fedor Sigaev (sigaev)
2017-12-12 11:23:01 Fedor Sigaev (sigaev) Changed committer to sigaev
2017-12-07 13:39:54 Alexander Korotkov (smagen) Changed authors to Alexander Korotkov (smagen)
2017-12-07 13:39:45 Alexander Korotkov (smagen) Attached mail thread CY4PR17MB13207ED8310F847CF117EED0D85A0@CY4PR17MB1320.namprd17.prod.outlook.com
2017-12-07 13:39:45 Alexander Korotkov (smagen) Created patch record