cubicweb-conference #968756 add tooltip to button "plan to attend" [resolved]

a tooltip would make it clear what action the user would take by clicking on the button, it could say "click here if you plan on attending this talk" when the button says "I do not plan to attend this".

done in0.6.0
load left0.000
closed by#38bd4fa5bc5e [views] improve the "plan to attend" user experience (closes #968756)