Fix example for Basis * Vector3 in documentation

[mart3323]

Description

This MR fixes an invalid example in the Basis documentation, fixes godotengine/godot-docs#9394

I opted to change the inputs instead of the outputs, because it seemed strange to have two identical basis vectors. Plus this allows some of the inputs to be negative

Actions performed

• Cloned both projects, symlinked them together and ran the build both before and after the changes to confirm they show up where expected
• Retested the GDScript example in editor to confirm the new example gives the promised result
• ⚠️ Did not test the C# example. Though I have no reason to believe it should run any different
• Checked the original MR to see if there were any comments about this example to be aware of
• Ran pre-commit hooks (4 passed, rest skipped)