pgsql: gen_node_support.pl: Mark location fields as type alias ParseLoc

gen_node_support.pl: Mark location fields as type alias ParseLoc

Instead of the rather ugly type=int + name ~= location$, we now have a
marker type for offset pointers or sizes that are only relevant when a
query text is included, which decreases the complexity required in
gen_node_support.pl for handling these values.

Author: Matthias van de Meent <boekewurm+postgres@gmail.com>
Discussion:
https://www.postgresql.org/message-id/flat/CAEze2WgrCiR3JZmWyB0YTc8HV7ewRdx13j0CqD6mVkYAW+SFGQ@mail.gmail.com

Branch
------
master

Details
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https://git.postgresql.org/pg/commitdiff/605721f819f5b603db6bc1405ef414747d182116

Modified Files
--------------
src/backend/nodes/gen_node_support.pl |  6 +--
src/include/nodes/nodes.h             |  9 ++++
src/include/nodes/parsenodes.h        | 92 +++++++++++++++++------------------
src/include/nodes/plannodes.h         |  4 +-
src/include/nodes/primnodes.h         | 72 +++++++++++++--------------
src/tools/pgindent/typedefs.list      |  1 +
6 files changed, 97 insertions(+), 87 deletions(-)