Parse IEC and ISO adoptions without "ISO" or "IEC" prefix

[mico]

Interestingly there is a way to tell IEC standards. IEC numbers start from 60000 to 79999. From 80000-89999 they are either ISO, IEC, or ISO/IEC or IEC/ISO standards. From 1 to 59999 it is only ISO.

Originally posted by @ronaldtse in metanorma/pubid-bsi#2 (comment)

Example: "BS EN 60038 AMD1 FRAG2"

[ronaldtse]

ISO Directives Part 1 writes:

https://www.iso.org/sites/directives/current/consolidated/index.xhtml

B.4.2.9

ISO-lead documents are assigned numbers from 1 to 59999. IEC-lead documents are assigned numbers from 60000 to 79999. In the case of multi-part standards, some parts being under ISO responsibility and some being under IEC responsibility, a number in the 80000 series is assigned (e.g. ISO 80000-1, IEC 80000-6).