Remaining uncovered Firefox locale ISO codes.

[DandelionSprout]

Provided that the 4 recentmost proposed ISO codes at gorhill/uBlock#3939 all get accepted, that would still leave 15 of Firefox's circa 101 language codes uncovered for reasons that are hard to mitigate. I decided to write about them in a Discussions thread instead of in the PR, so as to not distract from the PR's purpose.

• Primarily spoken in Anglosphere countries:
• • ach (Acholi, Uganda)
• • cy (Welsh)
• • ga (Irish)
• • gd (Scottish Gaelic)
• • sco ("Scots")
• • xh (Xhosa)
• Has no currently known regional lists:
• • eo (Esperanto)
• • hy (Armenian)
• • ia (Interlingua)
• • ka (Georgian)
• • km (Khmer)
• • my (Burmese)
• • tl (Tagalog, Philippines)
• • ur (Urdu)
• Ambiguous case:
• • az (Azerbaijani, a.k.a. Azeri); though it's been several years now since I last proposed to Team AdGuard to move their Azeri entries from AdGuard Base Foreign to AdGuard Turkish, they didn't seem sold on the idea at the time. I guess I could ask them again.