chore(AIP-143): Fix typo on "sovereignty" (#1586)

Author: jradcliff

aip/general/0143.md

@@ -93,7 +93,7 @@ format][] to represent this, and the field **must** be named `utc_offset`.
 
 The use of `region_code` instead of `country_code` is critical to being able to
 convey regions that are distinct from any country and to avoid any political
-disputes associated with said region regarding their soverignty or affiliation.
+disputes associated with said region regarding their sovereignty or affiliation.
 Google and many other companies are supporters of Unicode CLDR and standardize
 their product internationalization efforts on Unicode CLDR, and APIs are no
 different here. Furthermore, many of the values supported by Unicode CLDR are