added rewrites for inv(diag(x)) and inv(eye)

[tanish1729]

Description

Added rewrites for inv(diag(x)) = 1/x and rewrites inv(eye) -> eye

Related Issue

• [ ] Related to #573

Checklist

• [ ] Checked that the pre-commit linting/style checks pass
• [ ] Included tests that prove the fix is effective or that the new feature works
• [ ] Added necessary documentation (docstrings and/or example notebooks)
• [ ] If you are a pro: each commit corresponds to a relevant logical change

Type of change

• [ ] New feature / enhancement
• [ ] Bug fix
• [ ] Documentation
• [ ] Maintenance
• [ ] Other (please specify):