fix: Exit gracefully on artwork and sourcecode src file access errors

[kesara]

Fixes #1125

[rjsparks]

This changes the overall behavior to "exit on first error" rather than "list all errors". Is that necessary?
I think #1125 was complaining more about the lack of a human-readable interpretation of what had gone wrong than it was the stack trace hiding the error.

[kesara]

This changes the overall behavior to "exit on first error" rather than "list all errors". Is that necessary? I think #1125 was complaining more about the lack of a human-readable interpretation of what had gone wrong than it was the stack trace hiding the error.

This changes the overall behavior to "exit on first error" rather than "list all errors". Is that necessary? I think #1125 was complaining more about the lack of a human-readable interpretation of what had gone wrong than it was the stack trace hiding the error.

xml2rfc doesn't have a builtin functionality to list errors and not generate an output.
If we are to list these errors, xml2rfc will output something with empty art work/sourcecode.

EDIT: Exception being the parser, where it list errors and on-certain errors xml2rfc exits. But this happens after the parsing in prep stage.

[cabo]

xml2rfc doesn't have a builtin functionality to list errors and not generate an output.
If we are to list these errors, xml2rfc will output something with empty art work/sourcecode.

Which may be exactly what you want during editing the document.

(FYI, kramdown-rfc does not use src=.)