feat(language): support for Nushell language

[wu21-web]

Description

This PR addes language support for ocr for nushell, a new type of shell.
The nushell.md documentation is from the nushell-pro's references/script-review.md
Credits: @hustcer for repository hustcer/nushell-pro. @hustcer is a master at nushell.
hustcer/nushell-pro is MIT.

Type of Change

• Bug fix (non-breaking change that fixes an issue)
• New feature (non-breaking change that adds functionality)
• Breaking change (fix or feature that would cause existing functionality to change)
• Refactoring (no functional changes)
• Documentation update
• CI / Build / Tooling

How Has This Been Tested?

• make test passes locally
• Manual testing (describe below)

Checklist

• My code follows the project's coding style (go fmt, go vet)
• I have performed a self-review of my code
• I have added tests that prove my fix is effective or my feature works
• New and existing unit tests pass locally with my changes
• I have updated the documentation accordingly (if applicable)
• I have signed the CLA

Related Issues

closes #943

[github-actions]

✅ OpenCodeReview: Review complete: 0 finding(s) across 3 selected item(s).

[hustcer]

Signed