ci(docstring): add sphinx autodoc build test for docstring

GitOrigin-RevId: d6a4fd469a3c5759ab196a467485f9bc916393cd

imperative/python/scripts/sphinx.sh

+#!/bin/bash
+set -e
+
+# This script can be used to find WARNINGs and ERRORs hide in Python docstring.
+#
+# * Usually we use Sphinx (https://www.sphinx-doc.org/) and its' tools
+#   to build HTML documentation for Python projects, such as MegEngine. 
+# 
+# * It simulates the process of automatically extracting docstrings from source code
+#   and try generating HTML pages, just like what MegEngine documentation will do.
+#
+#   Install required Python dependence with pip then you will get following tools:
+#
+#   * sphinx-apidoc: a tool for automatic generation of Sphinx sources that,  
+#     using the autodoc extension,  document a whole package in the style of 
+#     other automatic API documentation tools. For more details: 
+#     https://www.sphinx-doc.org/en/master/man/sphinx-apidoc.html
+#
+#   * sphinx-build: generates documentation frome specific files. For more details:
+#     https://www.sphinx-doc.org/en/master/man/sphinx-build.html
+#
+# [NOTE]: You need build MegEngine first (target: develop) then run this script. 
+
+DOC_PATH=`mktemp -d`
+trap 'rm -rf "$DOC_PATH"' EXIT
+
+cd $(dirname $0)/..
+
+python3 -m pip install -r requires.txt
+python3 -m pip install -r requires-sphinx.txt
+sphinx-apidoc -f -F -e -o $DOC_PATH/source megengine "megengine/core/ops/builtin/*"
+PYTHONPATH=. sphinx-build -j auto -c . -W --keep-going \
+    $DOC_PATH/source $DOC_PATH/build