docs: link to description of South African ID

Reorder paragraphs in introduction.

README.md

@@ -7,10 +7,13 @@
 
 # South African ID for Laravel
 
+Validation rules and an Eloquent Model attribute cast to value object encapsulating a South African 
+government-issued personal [identification number](https://www.westerncape.gov.za/general-publication/decoding-your-south-african-id-number-0), 
+for Laravel.
+
 The validator will pass values generated by the Faker
 [idNumber](https://fakerphp.org/locales/en_ZA/#fakerprovideren_zaperson)
 formatter that is part of the English (South Africa) or `en_ZA` locale.
-Validation rules and an Eloquent Model attribute cast to value object encapsulating a South African government-issued personal identification number, for Laravel.
 
 ## Install