fix: add missing column in group by expression (#534)

when trying to use the lsp server autocompletion didnt work and when
activating logs found messages such as:

> ERROR pgt_lsp::session error=Database error: column "c.relkind" must
appear in the GROUP BY clause or be used in an aggregate function

upon adding c.relkind into the group by expression autocomplete started
working as expected, the issue seems to be using c.relkind in the select
statement without using it in the group by expression

I'm using postgres 12 to test it

---------

Co-authored-by: Nicolás De los Santos <nicolas.delossantos@meteologica.com>

Author: aokiji

.sqlx/query-66d92238c94b5f1c99fbf068a0b5cf4c296b594fe9e6cebbdc382acde73f4fb9.json renamed to .sqlx/query-aced4382cedbfc359bb1c1ab71cf2472fa8afc0b24bf02ee1bfdfdbf111acfc8.json

@@ -35,7 +35,8 @@ where
 group by
   c.oid,
   c.relname,
+  c.relkind,
   c.relrowsecurity,
   c.relforcerowsecurity,
   c.relreplident,
-  nc.nspname;
+  nc.nspname;