v3.4.7

• :flush-caches: no longer no-ops when :no-isobib-cache: is also set: relaton/relaton-iso#181
• Strip {{{ }}} delimiters when split across a subs=macros-injected element: metanorma/metanorma-pdfa#30, metanorma/metanorma#564
• Recognise [example%collapsible], emit collapsible="true": metanorma/metanorma-pdfa#31
• Recognise :supplement-number: in title_nums_prep: metanorma/metanorma-iso#1562
• Recognise the :toc-examples: document attribute (Table of Examples): metanorma/metanorma-pdfa#32