Short type mismatch for intervals between the doc and the implementation

[ajegou]

In the documentation short types for interval_day and interval_year are iday iyear:

but the code that does the mapping between type and short type uses day and year instead:

and substrait fails to find the function when loading a logical plan, for example:

java.lang.IllegalArgumentException: Unexpected scalar function with key date_bin:iday_tstz_tstz.
 The namespace ***.yaml is loaded but no scalar function with this key found.