am 40a0376e: docs: remove unused id attribute from Button

</pre>

<p>The height and width are set to <code>"wrap_content"</code> so the button is only as big as

necessary to fit the button's text.</p>

necessary to fit the button's text. This button doesn't need the 

<a href="{@docRoot}reference/android/view/View.html#attr_android:id">{@code android:id}</a>

attribute, because it won't be referenced from the activity code.</p>

        android:layout_width="0dp"

        android:layout_height="wrap_content"

        android:hint="@string/edit_message" />

    <Button android:id="@+id/button_send"

    <Button

        android:layout_width="wrap_content"

        android:layout_height="wrap_content"

        android:text="@string/button_send" />

attribute to the {@link android.widget.Button &lt;Button>} element:</p>

<pre>

<Button android:id="@+id/button_send"

<Button

    android:layout_width="wrap_content"

    android:layout_height="wrap_content"

    android:text="@string/button_send"