feed(derived-variables): the cover is framed for a card, and the next-release line goes

The cover is the same capture as the article's grid still - 1024 CSS px at 2x,
clipped to the rows - so the derived columns are legible on the feed card rather
than a thumbnail of a mostly-empty page.  It also stops promising the next
release, which is about to be stale.

content/feed/columns-that-are-not-in-the-table/index.md

@@ -18,7 +18,7 @@ It is never a five minute job - so Data Controller now does the obvious thing in
 
 The part that took the thinking is that they filter like any other column. That needed a DATA step view rather than a data step, and the reasoning is worth reading: [Derived variables: computed columns you can filter on](/derived-variables/).
 
-Ships with the next release. Reference: [Derived Variables](https://docs.datacontroller.io/derived-variables/).
+Reference: [Derived Variables](https://docs.datacontroller.io/derived-variables/).
 
 If a table of yours has been waiting for "just one more column", we would love to [hear from you](/contact).