chore: issue templates — drop missing triage label, MSRV 1.85

[Tuntii]

Issue templates apply a triage label that is not in the repo label set, so new issues land unlabeled. The bug template still says Rust 1.75.0; MSRV is 1.85. There is no config.yml.

Please:

• Add .github/ISSUE_TEMPLATE/config.yml with contact_links pointing at Discussions
• Remove triage from the three templates (or create the label)
• Bump the bug-template Rust placeholder from 1.75.0 to 1.85

YAML / docs only. Easy.

CONTRIBUTING: https://github.com/Tuntii/RustAPI/blob/main/CONTRIBUTING.md