pgsql: Print out error position for some ALTER TABLE ALTER COLUMN type

Print out error position for some ALTER TABLE ALTER COLUMN type

A ParseState exists in ATPrepAlterColumnType() since its introduction
in 077db40fa1f3, and it has never relied on a query string that could be
used to point at a location in the origin string on error.

The output of some regression tests are updated, showing the error
location where applicable. Six error strings are upgraded with the
error location.

Author: Jian He
Discussion: https://postgr.es/m/CACJufxGfbPfWLjcEz33G9eW_epDW0UDi2H05i9eSTPKGJ4rxSA@mail.gmail.com

Branch
------
master

Details
-------
https://git.postgresql.org/pg/commitdiff/65281391a937293db7fa747be218def0e9794550

Modified Files
--------------
src/backend/commands/tablecmds.c | 26 ++++++++++++++++----------
src/test/regress/expected/alter_table.out | 14 ++++++++++++++
src/test/regress/expected/generated_stored.out | 2 ++
src/test/regress/expected/typed_table.out | 2 ++
4 files changed, 34 insertions(+), 10 deletions(-)