添加复制button

在 docs/conf.py 文件中添加：

extensions = [
    'sphinx.ext.autodoc',
    'sphinx.ext.autosummary',
    'sphinx_rtd_theme',
    # 'numpydoc',
    'nbsphinx',
    'sphinx_copybutton',
    'sphinx-tabs',
]

添加代码块 Tabs：sphinx-tabs，文档 https://readthedocs.org/