`rustdoc --passes "collapse-docs unindent-comments"` doesn’t work is intended.
It still generate HTML files that look alright at a glance,
but all doc-comments are truncated to their first line
for some reason I don’t understand.
See http://doc.servo.org/script/dom/index.html for example.
The module documentation there is currently just
“The implementation of the DOM.”, but clicking the [src] link
shows a much larger doc-comment.
https://github.com/rust-lang/rust/issues/15347#issuecomment-122785714
The correct invokation is to use `--passes` multiple times.
