Merge branch 'jh-translation_guidelines' into 'master'

Add guidelines around avoiding translation updates

See merge request gitlab-org/gitlab!47078

doc/development/i18n/externalization.md

@@ -480,6 +480,21 @@ This makes use of [`Intl.DateTimeFormat`](https://developer.mozilla.org/en-US/do
 
 ## Best practices
 
+### Minimize translation updates
+
+Updates can result in the loss of the translations for this string. To minimize risks,
+avoid changes to strings, unless they:
+
+- Add value to the user.
+- Include extra context for translators.
+
+For example, we should avoid changes like this:
+
+```diff
+- _('Number of things: %{count}') % { count: 10 }
++ n_('Number of things: %d', 10)
+```
+
 ### Keep translations dynamic
 
 There are cases when it makes sense to keep translations together within an array or a hash.