Update parsers documentation

**Problem**
When working with data, the error messages could be more descriptive.

**Suggestion**
Improve error handling and add detailed error messages.

**Context**
This would help with debugging and maintenance.

The issue names no files, tests, or parser entry point. Start by locating the parsers and their existing error handling, then clarify which errors and messages are in scope. Done should mean the agreed parser errors provide detailed, useful messages and the documentation title reflects the resulting work.

Written by the indexing model from the issue text.