chore(about/index): update about
chore(about/index): update about

avigad/leanprover.github.io,soonhokong/leanprover.github.io,leanprover/leanprover.github.io,fpvandoorn/leanprover.github.io,soonhokong/leanprover.github.io,fpvandoorn/leanprover.github.io,avigad/leanprover.github.io,avigad/leanprover.github.io,leanprover/leanprover.github.io,soonhokong/leanprover.github.io,leanprover/leanprover.github.io,fpvandoorn/leanprover.github.io