mkDocs: Update for xz
mkDocs: Update for xz

Fixes #11419.

olsner/ghc,tjakway/ghcjvm,shlevy/ghc,vTurbine/ghc,olsner/ghc,ezyang/ghc,vikraman/ghc,sgillespie/ghc,sdiehl/ghc,oldmanmike/ghc,oldmanmike/ghc,tjakway/ghcjvm,shlevy/ghc,ezyang/ghc,mettekou/ghc,olsner/ghc,sgillespie/ghc,olsner/ghc,shlevy/ghc,sdiehl/ghc,mettekou/ghc,mcschroeder/ghc,shlevy/ghc,olsner/ghc,tjakway/ghcjvm,vikraman/ghc,ezyang/ghc,snoyberg/ghc,shlevy/ghc,sdiehl/ghc,vTurbine/ghc,vikraman/ghc,sgillespie/ghc,shlevy/ghc,tjakway/ghcjvm,mcschroeder/ghc,oldmanmike/ghc,tjakway/ghcjvm,ezyang/ghc,mcschroeder/ghc,vTurbine/ghc,vTurbine/ghc,snoyberg/ghc,sdiehl/ghc,oldmanmike/ghc,mettekou/ghc,olsner/ghc,snoyberg/ghc,vikraman/ghc,ezyang/ghc,shlevy/ghc,sdiehl/ghc,mettekou/ghc,sdiehl/ghc,tjakway/ghcjvm,olsner/ghc,mettekou/ghc,vikraman/ghc,vTurbine/ghc,snoyberg/ghc,snoyberg/ghc,ezyang/ghc,tjakway/ghcjvm,mcschroeder/ghc,vTurbine/ghc,mcschroeder/ghc,oldmanmike/ghc,vikraman/ghc,sgillespie/ghc,mettekou/ghc,sgillespie/ghc,mcschroeder/ghc,mcschroeder/ghc,snoyberg/ghc,vikraman/ghc,snoyberg/ghc,oldmanmike/ghc,vTurbine/ghc,mettekou/ghc,oldmanmike/ghc,sgillespie/ghc,sgillespie/ghc,ezyang/ghc,sdiehl/ghc