fix(library/tactic/intro_tactic): typo
fix(library/tactic/intro_tactic): typo

dselsam/lean,rlewis1988/lean,rlewis1988/lean,leanprover-community/lean,Kha/lean,leodemoura/lean,leanprover/lean,avigad/lean,fpvandoorn/lean,dselsam/lean,fpvandoorn/lean,fgdorais/lean,Kha/lean,digama0/lean,Kha/lean,johoelzl/lean,fpvandoorn/lean,soonhokong/lean-windows,dselsam/lean,rlewis1988/lean,leanprover-community/lean,Kha/lean,digama0/lean,leanprover-community/lean,leanprover/lean,leodemoura/lean,soonhokong/lean-osx,soonhokong/lean-osx,soonhokong/lean-windows,fgdorais/lean,digama0/lean,Kha/lean,rlewis1988/lean,fgdorais/lean,leanprover-community/lean,johoelzl/lean,avigad/lean,fgdorais/lean,leodemoura/lean,johoelzl/lean,leodemoura/lean,leanprover/lean,digama0/lean,soonhokong/lean-osx,johoelzl/lean,dselsam/lean,avigad/lean,leanprover/lean,soonhokong/lean-windows,soonhokong/lean-windows,leanprover/lean,leanprover-community/lean,avigad/lean,dselsam/lean,Kha/lean,soonhokong/lean-osx,leanprover-community/lean,fgdorais/lean,fpvandoorn/lean,digama0/lean,dselsam/lean,leodemoura/lean,rlewis1988/lean,soonhokong/lean-windows,digama0/lean,fpvandoorn/lean,avigad/lean,fpvandoorn/lean,soonhokong/lean-osx,leanprover/lean,avigad/lean,johoelzl/lean,johoelzl/lean,rlewis1988/lean,fgdorais/lean,leodemoura/lean