Last time I "fixed" this I left a `\` at the start of the string
to avoid an initial newline, but didn't realize it was a raw string.
This should fix it now for good.
Moved various documents into subdirectories, how-to and
reference.
Updated multiple links to use `:ref:` instead of `:doc:`,
meaning that files can henceforth be moved around without
breaking references.
Bruno Oliveira
pytest bot
Daniele Procida