pgsql: Tweak reformat_dat_file.pl to make it more easily hand-invokable

Tweak reformat_dat_file.pl to make it more easily hand-invokable.

Use the same code we already applied in duplicate_oids and unused_oids
to let this script find Catalog.pm without help. This removes the need
to supply a -I switch in most cases.

Also, mark the script executable, again to follow the precedent of
duplicate_oids and unused_oids. Now you can just do
"./reformat_dat_file.pl pg_proc.dat"
if you want to reformat only one or a few .dat files rather than all.

It'd be possible to remove the -I switches in the Makefile's convenience
targets, but I chose to leave them: they don't hurt anything, and it's
possible that in weird VPATH situations they might be of value.

Branch
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master

Details
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https://git.postgresql.org/pg/commitdiff/84549ebd4c4d1941006056cfb2455a4983fb15a2

Modified Files
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doc/src/sgml/bki.sgml | 2 +-
src/include/catalog/reformat_dat_file.pl | 26 ++++++++++++++------------
2 files changed, 15 insertions(+), 13 deletions(-)