Change suggestion window text color based on user feedback.

Changing highlight text color to black alpha=.87 and normal text
to black alpha=.57.

It turned out that alpha value is ignored if we set alpha value
and textColor at the same time. Using #AARRGGBB style instead.

Bug: 27389556
Change-Id: I318379261c66d9da089e8f8bf9f8136c10958511