Earlier the todo and poll widgets' UI differed a lot, especially in the
font size and weight, and the color and shape of the checkbox and vote
count box.
Now the font weights and sizes are consistent in both the widgets and
the todo widget's checkboxes and poll widget's vote count boxes are
styled similarly.
This is the rebased and cleaned version of #21006, and is visually near
identical.
Fixes: #20283.
N-Shar-ma