Somehow in RISC-V-Certification-Steering-Committee/riscv-isa-manual#11 the tags added to the ISA manual are causing node_text_context to be called with a "document" node name and Tim's tags.rb isn't expecting this. So, it raises an exception. I'm going to change it to a warning for now to make progress but Tim, can you help?
# Return the text content of a node. Adapted from `text-converter.rb`
# in the docs: https://docs.asciidoctor.org/asciidoctor/latest/convert/custom/
#
# node: AbstractNode
# returns: String
def node_text_content(node)
content_or_nil = case node.node_name
when "document"
warn "node_text_content(document) should be unreachable"
when "section"
"\n" + [node.title, node.content].join("\n").rstrip()
when "paragraph"
"\n" + normalize_space(node.content)