docs: Update README

Author: ignlg

README.md

@@ -40,12 +40,12 @@ heap vs array: push + top(50) of 100
 
 ### 2.0.x
 
-The main breaking change is that now _`top(N)` does NOT sort the output_. It should not be part of the spec for a priority queue, the output should be the top N elements. It will be _partially ordered_ by definition, that is all.
+The main breaking change is that now _`top(N)` does NOT sort the output_. It should not be part of the spec for a priority queue, the output should be the top N elements. It will be _partially ordered_ with the peek at index `0` by definition, that is all.
 
 - `top(N)` is unordered, only the first element is guaranteed to be the top priority element.
 - Fixes custom heap issue [#31](https://github.com/ignlg/heap-js/issues/31).
 - Performance improvements.
-- More tests, even for custom heaps.
+- More tests, including those for custom heaps.
 - Auxiliary experimental topN algorithms.
 - (wip) Benchmarks.