pgsql: Update display widths as part of updating Unicode

Update display widths as part of updating Unicode

The hardcoded "wide character" set in ucs_wcwidth() was last updated
around the Unicode 5.0 era. This led to misalignment when printing
emojis and other codepoints that have since been designated
wide or full-width.

To fix and keep up to date, extend update-unicode to download the list
of wide and full-width codepoints from the offical sources.

In passing, remove some comments about non-spacing characters that
haven't been accurate since we removed the former hardcoded logic.

Jacob Champion

Reported and reviewed by Pavel Stehule
Discussion: https://www.postgresql.org/message-id/flat/CAFj8pRCeX21O69YHxmykYySYyprZAqrKWWg0KoGKdjgqcGyygg(at)mail(dot)gmail(dot)com

Branch
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master

Details
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https://git.postgresql.org/pg/commitdiff/bab982161e0590746a2fd2a03043b27108b23ac6

Modified Files
--------------
src/common/unicode/.gitignore | 1 +
src/common/unicode/Makefile | 9 +-
.../generate-unicode_east_asian_fw_table.pl | 76 +++++++++++++
src/common/wchar.c | 41 +++----
src/include/common/unicode_east_asian_fw_table.h | 120 +++++++++++++++++++++
5 files changed, 220 insertions(+), 27 deletions(-)