Fix possible order changes for 'Powered by' in other languages

Since not all languages use the same word oder and we run into potential
issues, where the translation of powered by need to add something after
the CodiMD link, this should give us the needed flexiblity.

Signed-off-by: Sheogorath <sheogorath@shivering-isles.com>

locales/en.json

@@ -114,6 +114,6 @@
 	"Export user data": "Export user data",
 	"Help us translating on %s": "Help us translating on %s",
 	"Source Code": "Source Code",
-	"Powered by": "Powered by",
+	"Powered by %s": "Powered by %s",
 	"Register": "Register"
 }