pg_statistic MCVs use float4 but extended stats use float8

It seems odd that stats_ext uses double:

postgres=# SELECT attrelid::regclass, attname, atttypid::regtype, relkind FROM pg_attribute a JOIN pg_class c ON c.oid=a.attrelid WHERE attname='most_common_freqs';
attrelid | attname | atttypid | relkind
--------------------+-------------------+--------------------+---------
pg_stats | most_common_freqs | real[] | v
pg_stats_ext | most_common_freqs | double precision[] | v
pg_stats_ext_exprs | most_common_freqs | real[] | v

I'm not sure if that's deliberate ?

This patch changes extended stats to match.

--
Justin