Port over biocommons/hgvs#709 (Fix variant region for ins and dup on intron-exon boundary)

[holtgrewe]

Is your feature request related to a problem? Please describe.
The PR biocommons/hgvs#709 addresses issue biocommons/hgvs#655 that handles ins/del at intron/exon boundaries.

Describe the solution you'd like
Incorporate the patch and test as Rust code once merged in biocommons/hgvs.

Describe alternatives you've considered
N/A

Additional context

• Fix variant region for ins and dup on intron-exon boundary biocommons/hgvs#709
• Inconsistencies across intron/exon boundaries biocommons/hgvs#655