Tweak description in README.md

Author: vweevers

README.md

@@ -1,6 +1,6 @@
 # level-iterator-stream
 
-> Turn a leveldown iterator into a readable stream
+> Turn an [abstract-leveldown](https://github.com/Level/abstract-leveldown) iterator into a readable stream.
 
 [![level badge][level-badge]](https://github.com/Level/awesome)
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