There are only two measurement systems that locales use: US and metric.
For the former, move to copying the en_US locale, while for the latter,
move to copying the i18n locale. This lets us clean up all the stray
comments like FIXME.
There should be no functional differences here.
This updates a bunch of locales based on CLDR v28 data:
ar_SS: int_prefix: changing 249 to 211
bn_BD: int_prefix: changing 88 to 880
dz_BT: int_prefix: changing 66 to 975
en_HK: int_prefix: changing to 852
en_PH: int_prefix: changing to 63
en_SG: int_prefix: changing to 65
es_DO: int_prefix: changing 1809 to 1
es_PA: int_prefix: changing 502 to 507
es_PR: int_prefix: changing 1787 to 1
km_KH: int_prefix: changing 856 to 855
mt_MT: int_prefix: changing to 356
ne_NP: int_prefix: changing 91 to 977
pap_AW: int_prefix: changing 599 to 297
the_NP: int_prefix: changing 91 to 977
tk_TM: int_prefix: changing to 993
uz_UZ: int_prefix: changing 27 to 998
zh_SG: int_prefix: changing to 65
I've also checked these against https://countrycode.org/.
Note: the Dominican Republic (DO) and Puerto Rico (PR) updates are
correct: they both use +1. Historically, DO had one area code of
809 and PR of 787 which is why they were listed as such, but they
have both expanded into 829 and 989 respectively, so using the four
digit value is def incorrect now.
