Resolve "Docu"

Closes #5 (closed)

@mgoebel Do you think that the convention for attribute assignment (Doc/Span/Span via dict) is comprehensible? https://gitlab.gwdg.de/text-plus-collections/mona-pipe/-/blob/develop/src/monapipe/docs/development/custom_component.md?ref_type=heads&plain=1#L48