[llvm] [Github][CI] Add `doc8` to Dockerfile (PR #172256)

[via llvm-commits]

https://github.com/zeyi2 created https://github.com/llvm/llvm-project/pull/172256

This is needed by https://github.com/llvm/llvm-project/pull/172123 to avoid potential CI failures.

>From a24be0ca10b7c713794db061f043b997e3236eb9 Mon Sep 17 00:00:00 2001
From: mtx <mitchell.xu2 at gmail.com>
Date: Mon, 15 Dec 2025 14:19:23 +0800
Subject: [PATCH] [Github][CI] Add `doc8` to Dockerfile

---
 .../workflows/containers/github-action-ci-tooling/Dockerfile  | 4 ++++
 1 file changed, 4 insertions(+)

diff --git a/.github/workflows/containers/github-action-ci-tooling/Dockerfile b/.github/workflows/containers/github-action-ci-tooling/Dockerfile
index b78c99efb9be3..8d02baa05f489 100644
--- a/.github/workflows/containers/github-action-ci-tooling/Dockerfile
+++ b/.github/workflows/containers/github-action-ci-tooling/Dockerfile
@@ -94,6 +94,10 @@ COPY --from=llvm-downloader /llvm-extract/LLVM-${LLVM_VERSION}-Linux-X64/bin/cla
 COPY clang-tools-extra/clang-tidy/tool/clang-tidy-diff.py ${LLVM_SYSROOT}/bin/clang-tidy-diff.py
 
 # Install dependencies for 'pr-code-lint.yml' job
+RUN apt-get update && \
+    DEBIAN_FRONTEND=noninteractive apt-get install -y python3-doc8 && \
+    apt-get clean && \
+    rm -rf /var/lib/apt/lists/*
 COPY llvm/utils/git/requirements_linting.txt requirements_linting.txt
 RUN pip install -r requirements_linting.txt --break-system-packages && \
     rm requirements_linting.txt