Doc-deprecate

Ref Level/community#113

README.md

@@ -2,6 +2,8 @@
 
 **Concatenate entries from an iterator into an array.**
 
+> :pushpin: This module will soon be [deprecated](https://github.com/Level/community/issues/113), because its functionality is included in [`abstract-level`](https://github.com/Level/abstract-level).
+
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