Remove bold style from list of contributing pages.
Remove bold style from list of contributing pages.

This same style was previously removed from the docs page. It's not needed.

starsep/rust-www,starsep/rust-www,AndrewBrinker/rust-www,AndrewBrinker/rust-www,ituxbag/rust-www,AndrewBrinker/rust-www,starsep/rust-www,starsep/rust-www,starsep/rust-www,ituxbag/rust-www,ituxbag/rust-www,ituxbag/rust-www,AndrewBrinker/rust-www,AndrewBrinker/rust-www,ituxbag/rust-www,AndrewBrinker/rust-www,starsep/rust-www,ituxbag/rust-www