BSI: corrigendum tags encoding

[Intelligent2013]

From https://github.com/metanorma/mn-samples-bsi/issues/312:

add:[C1] or change-begin:[C1] and del:[C1] or change-end:[C1] turns into:

[[anchor1]] ... [[anchor2]] ... [[anchor3]] ... [[anchor4]]

[reviewer=A1,type=corrigenda,from=anchor1,to=anchor3]
****
****

This means you will need to add bookmarks [[...]] into the text, where the corrigenda tags occur inline. So the table example above becomes:

[reviewer=A1,from=anchor1,to=anchor2,type=corrigenda]
****
****


[cols=3]
|===
|[[anchor1]]IIB-P or Q 
| Portland cement with 21% to 35% pozzolana 
| CEM II/B-P or Q, CIIB-P or Q [[anchor2]]
|===

Currently, mnconvert generates add:[ace-tag..._start] and `add:[ace-tag..._end] for

Example:

add:[ace-tag_A1_start] Other than in the case of the exceptions listed in ....add:[ace-tag_A1_end]