Show an example of using fenced fiv to create the div of id refs for pandoc citeproc

[cderv]

This should be improved here:
https://bookdown.org/yihui/rmarkdown-cookbook/bibliography.html#include-appendix-after-bibliography

# References

::: {#refs}
:::

# (APPENDIX) Appendix {-} 

# More information

This will be Appendix A.

# One more thing

This will be Appendix B.

Other related biblio improvement #328