Remove warning about std::map::emplace

styleguide/c++/c++11.html

Index: styleguide/c++/c++11.html
diff --git a/styleguide/c++/c++11.html b/styleguide/c++/c++11.html
index 1700149d9b345699d4b98f5b261e6f5688da38f0..932abaa4396228e07632e7be72b7e133bb2e80b7 100644
--- a/styleguide/c++/c++11.html
+++ b/styleguide/c++/c++11.html
@@ -404,7 +404,7 @@ template &lt;typename T&gt;<br/>void Function(T&amp;&amp; t) { ... }</code></td>
 <td><code>emplace()</code>, <code>emplace_back()</code>, <code>emplace_front()</code>, <code>emplace_hint()</code></td>
 <td>Constructs elements directly within a container without a copy or a move. Less verbose than <code>push_back()</code> due to not naming the type being constructed.</td>
 <td>E.g. <a href="http://en.cppreference.com/w/cpp/container/vector/emplace_back">std::vector::emplace_back</a></td>
-<td><code>std::map::emplace()</code> is not yet available on all libstdc++ versions we support. When using emplacement for performance reasons, your type should probably be movable (since e.g. a vector of it might be resized); given a movable type, then, consider whether you really need to avoid the move done by <code>push_back()</code>. For readability concerns, treat like <code>auto</code>; sometimes the brevity over <code>push_back()</code> is a win, sometimes a loss. <a href="https://groups.google.com/a/chromium.org/forum/#!topic/cxx/m3cblzEta7A">Discussion thread</a></td>
+<td>When using emplacement for performance reasons, your type should probably be movable (since e.g. a vector of it might be resized); given a movable type, then, consider whether you really need to avoid the move done by <code>push_back()</code>. For readability concerns, treat like <code>auto</code>; sometimes the brevity over <code>push_back()</code> is a win, sometimes a loss. <a href="https://groups.google.com/a/chromium.org/forum/#!topic/cxx/m3cblzEta7A">Discussion thread</a></td>
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