- Templates scope state changes
- State-modifying function operate in place instead of returning a template
- Internal template representation contains actual owned nodes instead of a pointer to a syntax tree + an expression map
- No more wide calls
- Reorder parser methods and use `Pos` everywhere
- Remove tab special handling for columns and adapt heading/list/enum indent handling
- Don't panic when a file has an empty path
- Makes errors fatal, so that a phase is only reached when all previous phases were error-free
- Parsing still recovers and can produce multiple errors
- Evaluation fails fast and can thus produce only a single error (except for parse errors due to an import)
- The single error that could occur during execution is removed for now
- Removes Value::Error variant
