dictionary: add regoin->region

Observed in our codebase.

Author: thiagowfx

codespell_lib/data/dictionary.txt

@@ -49440,6 +49440,7 @@ regnerated->regenerated
 regnerates->regenerates
 regnerating->regenerating
 regneration->regeneration
+regoin->region
 regon->region
 regons->regions
 regorded->recorded