Use choose without otherwise

An xsl:choose without an xsl:otherwise branch silently produces no output when no xsl:when condition matches. Add xsl:otherwise to handle unexpected values explicitly.

Incorrect:

<xsl:choose>
  <xsl:when test="@type = 'a'">A</xsl:when>
  <xsl:when test="@type = 'b'">B</xsl:when>
</xsl:choose>

Correct:

<xsl:choose>
  <xsl:when test="@type = 'a'">A</xsl:when>
  <xsl:when test="@type = 'b'">B</xsl:when>
  <xsl:otherwise>Unknown</xsl:otherwise>
</xsl:choose>