Add next / prev links to vertical-align docs. Add mdn reference link.
Add next / prev links to vertical-align docs.
Add mdn reference link.

fenderdigital/css-utilities,fenderdigital/css-utilities,cwonrails/tachyons,tachyons-css/tachyons,getfrank/tachyons,topherauyeung/portfolio,pietgeursen/pietgeursen.github.io,matyikriszta/moonlit-landing-page,topherauyeung/portfolio,topherauyeung/portfolio