tools: eslint rule for missing internal/error doc

1. Adds a lint rule to catch undocumented internal/errors
2. Adds docs for missing internal/error codes

Checklist

• make -j4 test (UNIX), or vcbuild test (Windows) passes
• tests and/or benchmarks are included
• documentation is changed or added
• commit message follows commit guidelines

Affected core subsystem(s)

doc, tools