* Improve label wrapping
- Adjust issue list styles so labels can wrap on the same line as the
text. This relies on `display: inline` with the HTML whitespace being
used as the separator.
- Add global word-break: break-word. This should generally avoid text
overflows in various places.
* add whitespace to history labels
* use overflow-wrap
* restore word-break rules
* use correct pre
* use better selector for middle align
Co-authored-by: Lunny Xiao <xiaolunwen@gmail.com>