Docs: Order of json aggregate functions

The order of json related aggregate functions in the docs is currently 
like this:

[...]
json_agg
json_objectagg
json_object_agg
json_object_agg_strict
json_object_agg_unique
json_arrayagg
json_object_agg_unique_strict
max
min
range_agg
range_intersect_agg
json_agg_strict
[...]

json_arrayagg and json_agg_strict are out of place.

Attached patch puts them in the right spot. This is the same down to v16.

Best,

Wolfgang