Adjust h3 size to keep it smaller than h2 across normal platforms

Adjust h3 size to keep it smaller than h2 across normal platforms

Some platforms (especially certain linux distros) use slightly wider
sans-serifs than others by default. Bolding these wider fonts has a
more significant size impact than with narrower ones, so because the
h3 is bold and the h2 is not, a little more distance between their
defined sizes should ensure that the h3 will remain smaller than the
h2 regardless of platform.

Bug: 69999
Change-Id: I667c60f553d67e5208c708446f13b0773ad11ace