data/iso_3166-1.json: add missing common names

Add missing common names for Laos, Iran, and Syria. These are from remarks about common names in the ISO.org online browsing platform.

• See: https://www.iso.org/obp/ui/#iso:code:3166:LA
• See: https://www.iso.org/obp/ui/#iso:code:3166:IR
• See: https://www.iso.org/obp/ui/#iso:code:3166:SY