Display for tei:choice and child elements

[wlpotter]

Text may be tagged with a tei:choice element and a set of the following pairs of elements:

• tei:sic and tei:corr
• tei:orig and tei:reg
• tei:abbr and tei:expan

We would like what is in the first of these pairs (sic, orig, or abbr) to display as normal. The second of these pairs (corr, reg, or expan) should be displayed inside square brackets, '[' and ']'.

Example (from https://bl.syriac.uk/ms/1147#msPart1, item number 7):

<rubric xml:lang="syr">ܡܛܠ ܩܘ̈ܦܐ ܕܗ̣ܘ 
  <choice>
    <sic>ܒܘܙܢܢܗ̇</sic>
    <corr resp="https://bl.syriac.uk/documentation/editors.xml#wwright">ܒܘܙܝܢܗ</corr>
  </choice>
</rubric>

Display as: "ܡܛܠ ܩܘ̈ܦܐ ܕܗ̣ܘ ܒܘܙܢܢܗ̇ [ܒܘܙܝܢܗ]"

[wsalesky]

Done: https://github.com/srophe/britishLibrary/issues/328