Port over biocommon/hgvs#719 (Fix ins or dups where splice region is preserved)

[holtgrewe]

Is your feature request related to a problem? Please describe.
The PR biocommons/hgvs#719 addresses issue biocommons/hgvs#714 that handles ins/del where the splice region is preserved.

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

• c_to_p at intron/exon boundary where splice region is preserved biocommons/hgvs#714
• Fix ins or dups where splice region is preserved biocommons/hgvs#719