YAML not recognized, defaulting to Markdown

[WelliSolutions]

When I run make, I get the following warning:

pandoc details.yml -o output.pdf --template=template.tex --pdf-engine=xelatex
[WARNING] Could not deduce format from file extension .yml
  Defaulting to markdown

That doesn't seem right, IMO. We can't treat YAML as Markdown, can we?

[WelliSolutions]

Okay, the YAML file seems to be a markdown file with a YAML Metadata block: https://pandoc.org/MANUAL.html#extension-yaml_metadata_block

To get rid of the warning, we can specify the format in the makefile:

$(TEX) -f markdown+yaml_metadata_block $(filter-out $<,$^ ) -o $@ --template=$< $(FLAGS)