Description

This PR updates the interface for parsers in oxvg_ast to avoid dependance on implementation details for consumers.

Motivation and Context

For ease of use by consumers.

How Has This Been Tested?

• Units tests
• w3c & oxygen

Types of changes

Fixes

• Fixes compilation error for markup5ever parser
• perf: Pre-allocates arena with capacity
• Fix rustdocs

Breaking changes

• Changes parsing API

Checklist:

• My code follows the code style of this project.
• My change requires a change to the documentation.
• I have updated the documentation accordingly.
• I have added tests to cover my changes.
• All new and existing tests passed.