[commit: packages/containers] master: Update changelog (6414704)

[git at git.haskell.org]

Repository : ssh://git@git.haskell.org/containers

On branch  : master
Link       : http://git.haskell.org/packages/containers.git/commitdiff/6414704b892a6dc56a1b17e3a530d777b70f56ae

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commit 6414704b892a6dc56a1b17e3a530d777b70f56ae
Author: David Feuer <David.Feuer at gmail.com>
Date:   Sat Apr 1 12:01:22 2017 -0400

    Update changelog


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6414704b892a6dc56a1b17e3a530d777b70f56ae
 changelog.md | 2 ++
 1 file changed, 2 insertions(+)

diff --git a/changelog.md b/changelog.md
index 418406a..42b4b33 100644
--- a/changelog.md
+++ b/changelog.md
@@ -22,6 +22,8 @@
 * Optimize `Data.IntMap.restrictKeys` and `Data.IntMap.withoutKeys`. The
   semantic fix in 0.5.10.1 left them rather slow in certain cases.
 
+* Speed up `size` for `IntSet` and `IntMap` (thanks, Mike Ledger!).
+
 * Define a custom `liftA2` in `Applicative` instances for base 4.10, and use
   `liftA2` rather than `<*>` whenever it may be beneficial.