Building HTML documentation instructions fails on clean clone

[oeb25]

When cloning a fresh version of mathlib (9610549 specifially) and running the instructions for building the HTML documentation fails with:

❯ lake -R -Kdoc=on update doc-gen4
  lake build Mathlib:docs
info: batteries: cloning https://github.com/leanprover-community/batteries to '././.lake/packages/batteries'
info: Qq: cloning https://github.com/leanprover-community/quote4 to '././.lake/packages/Qq'
info: aesop: cloning https://github.com/leanprover-community/aesop to '././.lake/packages/aesop'
info: proofwidgets: cloning https://github.com/leanprover-community/ProofWidgets4 to '././.lake/packages/proofwidgets'
info: importGraph: cloning https://github.com/leanprover-community/import-graph to '././.lake/packages/importGraph'
info: Cli: cloning https://github.com/leanprover/lean4-cli to '././.lake/packages/Cli'
info: mathlib: running post-update hooks
error: unknown library facet `docs`

System information:

❯ elan --version
elan 3.1.1 (71ddc6633 2024-02-22)

❯ lean --version
Lean (version 4.10.0, arm64-apple-darwin23.5.0, commit c375e19f6b65, Release)

❯ lake --version
Lake version 5.0.0-c375e19 (Lean version 4.10.0)

[oeb25]

This might be related to leanprover-community/batteries#669 but the current docs already has the -R flag, so I'm not quite sure.