Rework pg_input_error_message(), now renamed pg_input_error_info()

pg_input_error_info() is now a SQL function able to return a row with
more than just the error message generated for incorrect data type
inputs when these are able to handle soft failures, returning more
contents of ErrorData, as of:
- The error message (same as before).
- The error detail, if set.
- The error hint, if set.
- SQL error code.

All the regression tests that relied on pg_input_error_message() are
updated to reflect the effects of the rename.

Per discussion with Tom Lane and Andrew Dunstan.

Author: Nathan Bossart
Discussion: https://postgr.es/m/139a68e1-bd1f-a9a7-b5fe-0be9845c6311@dunslane.net

contrib/ltree/sql/ltree.sql

@@ -393,7 +393,10 @@ SELECT count(*) FROM _ltreetest WHERE t ? '{23.*.1,23.*.2}' ;
 
 SELECT str as "value", typ as "type",
        pg_input_is_valid(str,typ) as ok,
-       pg_input_error_message(str,typ) as errmsg
+       errinfo.sql_error_code,
+       errinfo.message,
+       errinfo.detail,
+       errinfo.hint
 FROM (VALUES ('.2.3', 'ltree'),
              ('1.2.', 'ltree'),
              ('1.2.3','ltree'),
@@ -402,4 +405,5 @@ FROM (VALUES ('.2.3', 'ltree'),
              ('1.2.3','lquery'),
              ('$tree & aWdf@*','ltxtquery'),
              ('!tree & aWdf@*','ltxtquery'))
-      AS a(str,typ);
+      AS a(str,typ),
+     LATERAL pg_input_error_info(a.str, a.typ) as errinfo;