The way `(lib.formats.yaml {}).generate` generates YAML is compliant
because on YAML 1.2 spec JSON is a subset of YAML but it bugs people's
minds and can lead to problems with software that is not compatible with
YAML 1.2.
This commit also changes the test of the generation function. Data
validation/typing remains the same.
See #133802.
Signed-off-by: lucasew <lucas59356@gmail.com>
Foremost, the message was discarding double quotes on one side of the
diff, which was super-confusing to me, as I thought that the format
convertor broke that when in fact only whitespace was changed.
I thought I'd cat the files, but then... switching to `diff -u` seemed
self-sufficient. It felt sufficiently non-controversial to push
directly, but certainly feel free to improve further.
