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