docs: add allowembedded

<dl class="xml">

<dt>syntax:</dt>

<dd><pre class="stx">&lt;activity android:<a href="#reparent">allowTaskReparenting</a>=["true" | "false"]

<dd><pre class="stx">&lt;activity android:<a href="#embedded">allowEmbedded</a>=["true" | "false"]

          android:<a href="#reparent">allowTaskReparenting</a>=["true" | "false"]

          android:<a href="#always">alwaysRetainTaskState</a>=["true" | "false"]

          android:<a href="#clear">clearTaskOnLaunch</a>=["true" | "false"]

          android:<a href="#config">configChanges</a>=["mcc", "mnc", "locale",

<dt>attributes:</dt>

<dd><dl class="attr">

<dt><a name="embedded"></a>{@code android:allowEmbedded}</dt>

<dd>

    Indicate that the activity can be launched as the embedded child of another

    activity. Particularly in the case where the child lives in a container

    such as a Display owned by another activity. For example, activities

    that are used for Wear custom notifications must declare this so

    Wear can display the activity in it's context stream, which resides

    in another process.

    <p>The default value of this attribute is <code>false</code>.

</dd>

<dt><a name="reparent"></a>{@code android:allowTaskReparenting}</dt>

<dd>Whether or not the activity can move from the task that started it to

the task it has an affinity for when that task is next brought to the