Mathics3 9.0.0 is out

[rocky]

Some fundamental improvements move us closer to WMA conformance.

Some of the important changes:

• Significant progress on box operator parsing and scanning escape sequences properly
• Rule selection for pattern matching more closely follows WMA
• Assignment operators isolate left-hand-side references.
• Interrupt handling added
• Debugging capabilities improved
• We start to track locations which is used in errors and in debugging better

What remains to be updated are the conglomerates Mathics3 omnibus and updating pyodide. I will try to update these soon.