Add Corsican localization (#7390)

* Added Corsican localization

* Declaring Corsican localization

* Fixed activerecord locale

* Added a missing translation and switched to French-style apostrophes

* Fixed a (predictable) mistake made while bulk-replacing apostrophes

* More fixing

* i18n-tasks normalize

config/locales/activerecord.co.yml

@@ -0,0 +1,13 @@
+---
+co:
+  activerecord:
+    errors:
+      models:
+        account:
+          attributes:
+            username:
+              invalid: solu lettere, numeri è liniette basse
+        status:
+          attributes:
+            reblog:
+              taken: di u statutu esista digià