Updating FAQ to mention Indonesian case (#2774)

FAQ.md

@@ -8,10 +8,11 @@ In some cases, the library cannot tell if the leading digits of a phone number
 are intended to be the country calling code, or the start of the national
 significant number.
 
-This affects primarily German phone numbers, where 49 is both a country calling
-code and an area code, and numbers of variable lengths are valid. The leading
-digits will only be interpreted as a country calling code if the number is not
-already considered a possible number for the region provided when parsing.
+This affects primarily German and Indonesian phone numbers, where country
+calling code (49 and 62 respectively) is also a valid area code, and numbers of
+variable lengths are valid. The leading digits will only be interpreted as a
+country calling code if the number is not already considered a possible number
+for the region provided when parsing.
 
 If you know that your numbers are always in the form <country calling
 code><national significant number>, it is safe to put a "+" in front to