Add "last" action to move the cursor to the last match

This is the opposite of "first" (previously known as "top").

CHANGELOG.md

@@ -23,6 +23,9 @@ CHANGELOG
   # Write "regular" if you want to clear the attributes
   fzf --color hl:176:regular,hl+:177:regular
   ```
+- Added `last` action to move the cursor to the last match
+    - The opposite action `top` is renamed to `first`, but `top` is still
+      recognized as a synonym for backward compatibility
 
 0.24.4
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