Query function arg data types ONLY (no arg names)

[Jeremy Finzel]

It appears that neither pg_get_function_arguments
nor pg_get_function_identity_arguments could be used for this.  I want to
get function argument data types from the catalog by ordinal position,
without the argument name.

For example, I want the same information for these 2 functions:

foo(p_1 int, p_2 text)

- {int, text}

foo(int, text)

- {int, text}

Any suggestions as to how to use the catalogs or built-in postgres
functions to query this?

Thank you!
Jeremy