Catch up changelog.txt with recent languages changes

Ok, as per my records, we need the following covered:

#253157: Add "Translate own content" permission, rename "Translate content" to "Translate all content" - included in patch.
#322995: Provide a distinct administration user interface language option - in patch
#1280996: New language_select element type for form API - in patch in some way

So looks like all are somewhat covered :)

As for the patch itself:

+++ b/core/CHANGELOG.txtundefined
@@ -46,6 +46,8 @@ Drupal 8.0, xxxx-xx-xx (development version)
+      * Added new permissions that made translation permissions more granular.

IMHO make it "Unified content translation permission granularity with content editing permissions."

+++ b/core/CHANGELOG.txtundefined
@@ -79,6 +81,7 @@ Drupal 8.0, xxxx-xx-xx (development version)
+      * Added language select form element in the Form API

I'd add an item for "Made it possible to assign language to taxonomy terms and vocabularies." somewhere in the content list and add a dot at the end of this one :)

Also, this one is best in the docs component.

Made the suggested changes. The taxonomy and vocabulary language assignment already had a changelog item (even though we only introduced it on the backend earlier), so left it there.

One minor edit:

+      * Introduced the possibility of an administration specific language 

This should be administration-specific (with a hyphen). But I doubt the rest of the changelog is following English punctuation rules either... so it's probably OK to go in as-is.

Haha, thanks!

I made that fix on commit, and also removed a couple of end-of-line spaces (one from this patch and one that was there from before).

Thanks all, moving off sprint!