feature: Add tests for known errors

[jpt13653903]

Did you check the tree-sitter docs?

• I have read all the tree-sitter docs if it relates to using the parser

Is your feature request related to a problem? Please describe.

All existing tests are positive-only, and does not test expected error cases. Examples include literal formatting details such as space and underscore placement.

Describe the solution you'd like

Use this advice to implement expected error-related tests.

Describe alternatives you've considered

N/A

Additional context

N/A

[jpt13653903]

The test passes with or without the error, making the endeavour useless.