Add i18n keys to handle distance_of_time_in_words_to_now result

- This method is already translated thanks to rails-i18n, but it is missing few langages such as 'fr_BE'. Adding those keys makes it possible to have the translation.
 - Adding translations to `en.yml` could be seen as useless (since is already correctly handled by rails-i18n) but this is the way we process i18n issues.

config/locales/en.yml

@@ -3794,3 +3794,42 @@ See the %{link} to find out more about %{sitename}'s features and to start using
         spree/payment:
           one: Payment
           other: Payments
+  datetime:
+    distance_in_words:
+      about_x_hours:
+        one: about 1 hour
+        other: about %{count} hours
+      about_x_months:
+        one: about 1 month
+        other: about %{count} months
+      about_x_years:
+        one: about 1 year
+        other: about %{count} years
+      almost_x_years:
+        one: almost 1 year
+        other: almost %{count} years
+      half_a_minute: half a minute
+      less_than_x_seconds:
+        one: less than 1 second
+        other: less than %{count} seconds
+      less_than_x_minutes:
+        one: less than a minute
+        other: less than %{count} minutes
+      over_x_years:
+        one: over 1 year
+        other: over %{count} years
+      x_seconds:
+        one: 1 second
+        other: "%{count} seconds"
+      x_minutes:
+        one: 1 minute
+        other: "%{count} minutes"
+      x_days:
+        one: 1 day
+        other: "%{count} days"
+      x_months:
+        one: 1 month
+        other: "%{count} months"
+      x_years:
+        one: 1 year
+        other: "%{count} years"