STS -> MN: Figure with key should be encoded as a Key

[ronaldtse]

Document: https://github.com/metanorma/mn-samples-bsi/blob/main/reference-docs/bs-codes-of-practice/bs-7273-4-2015-A1-2021/30422111.xml

Output now:

[[fig_1]]
.Scope of <<BS_7273_4>>
image::2013-02348_BS7273-4_01.png[]

[[array_tab_a]]
[%unnumbered]
[cols="1800,2099,288,5813",width=618px]
|===

| *Key* a|[align=justified]
  a|[align=justified]
  a|[align=justified]

a|[%unnumbered]
image::2013-02348_BS7273-4_01KEY1.png[]
 3+|Within the scope of this standard
a|[%unnumbered]
image::2013-02348_BS7273-4_01KEY2.png[]
 3+|Outside the scope of this standard
4+|1) Any special recommendations for provision and siting of fire detectors and {{manual call point,manual call points}} are within the scope of this standard. +
2) The effect of failures of power supply for the devices is within the scope of this standard.

|===

Should be:

.Scope of <<BS_7273_4>>
====
image::2013-02348_BS7273-4_01.png[]

[%key]
image:2013-02348_BS7273-4_01KEY1.png[] {blank}:: Within the scope of this standard
image:2013-02348_BS7273-4_01KEY2.png[] {blank}:: Outside the scope of this standard

NOTE: Any special recommendations for provision and siting of fire detectors and {{manual call point,manual call points}} are within the scope of this standard. +

NOTE: The effect of failures of power supply for the devices is within the scope of this standard.
====

[Intelligent2013]

The source NISO STS XML represents as 4-columns table, without any information that last row relates to the notes:

<array id="tab_a">
	<table width="618">
		<colgroup>
			<col width="18%"/>
			<col width="20.99%"/>
			<col width="2.88%"/>
			<col width="58.13%"/>
		</colgroup>
		<tbody>
			<tr>
				<td valign="middle" colspan="4" align="center" scope="col">
					<graphic xlink:href="2013-02348_BS7273-4_01"/>
				</td>
			</tr>
			<tr>
				<td valign="top" align="left" scope="row">
					<bold>Key</bold>
				</td>
				<td valign="top" align="justify"> </td>
				<td valign="top" align="justify"> </td>
				<td valign="top" align="justify"> </td>
			</tr>
			<tr>
				<td valign="top" align="left" scope="row">
					<graphic xlink:href="2013-02348_BS7273-4_01KEY1"/>
				</td>
				<td colspan="3" valign="top" align="left">Within the scope of this standard</td>
			</tr>
			<tr>
				<td valign="top" align="left" scope="row">
					<graphic xlink:href="2013-02348_BS7273-4_01KEY2"/>
				</td>
				<td colspan="3" valign="top" align="left">Outside the scope of this standard</td>
			</tr>
			<tr>
				<td colspan="4" valign="top" align="left" scope="col">1) Any special recommendations for provision and siting of fire detectors and <named-content content-type="term" xlink:href="#term_3.26">manual call points</named-content> are within the scope of this standard.<p>2) The effect of failures of power supply for the devices is within the scope of this standard.</p>
				</td>
			</tr>
		</tbody>
	</table>
</array>

I don't have clear view how this table may be converted to figure with key adoc structure.