replace tabs to spaces at public/help/wiki_syntax_detailed.html
Removed useless code.
Backported r8686 from trunk (#10013).
Merged r8568 from trunk (#9937).
Merged r8231, r8235, r8236, 8237 from trunk (#9795).
Merged r8258 from trunk (#9793).
Merged r8210 from trunk (#9792).
Merged r8209 from trunk (#9775).
Fixed rounding issue on spent hours column in CSV export (#10150).
Merged r8761 from trunk
attachment: fix that diff type is not saved in user preference.
