Create bolder warnings for people to not use returns table and returns setof record and out/inout parameters

[benjie]

They work, but they're hard to work with; see: https://postgraphile.org/postgraphile/next/customization-overview/#adding-a-field-to-a-function-derived-type

[benjie]

See also this comment from me on how anonymous types are handled and why you should use setof:

#2331 (comment)

There's also another example in a follow-up comment in that same thread.

[benjie]

Noted by @machineghost in #2331 (comment):

As a side note, returns table is extremely popular in Stack Overflow PostgreSQL function examples, so anyone learning from SO (ie. a very healthy percentage of Postgraphile users) will be copying function code with returns table. Perhaps this "advice" should be a big/bold/visible warning.

It may also be worth warning about this in PostGraphile's console output, maybe. Something like:

Warning: The function schema_name.function_name uses {returns table | out/inout arguments} which means that the type it returns is "anonymous". Anonymous types are very hard to augment in PostGraphile, we recommend that you instead return a new (or existing) named type - the body of your function does not need to change, only the return type - for instructions, see https://err.red/pnt

[machineghost]

I like the idea. Some people might miss it in all the console spam, but it will help many others.