Ignore a type but still document its fields when embedded

#73 changed (fixed) the behavior of `ignoreTypes` so that they are actually excluded from the output. I was previously using the `ignoreTypes` list to ignore types that are only embedded in other structs. The types would not receive their own section/table in the resulting docs, but their fields would still be documented when they were embedded in other structs (with `json:",inline"`). It would be nice if this use case could be supported in the tool.

Start by tracing the ignoreTypes behavior changed in #73 and the handling of embedded structs marked json:",inline". Confirm how ignored types are excluded while their embedded fields remain in generated documentation, then add coverage for this case and verify the generated output.

Written by the indexing model from the issue text.