Update (#934)

* update doc

* update demos

* update docs

---------

Co-authored-by: Ren Xuancheng <17811943+jklj077@users.noreply.github.com>

docs/README.md

@@ -20,7 +20,7 @@ The documentation is available in both English and Simplified Chinese. We use
 
 You need to install the Python package `sphinx-intl` before starting.
 
-1. After updating the English documentation, run `make gettext`, and the pot files will be placed in the `build/gettext` directory.
+1. After updating the English documentation, run `make gettext`, and the pot files will be placed in the `build/gettext` directory. `make gettext` can be slow if the doc is long.
 
 2. Use the generated pot files to update the po files:
     ```bash
@@ -29,4 +29,22 @@ You need to install the Python package `sphinx-intl` before starting.
 
 3. Translate po files at `locales\zh_CN\LC_MESSAGES`. Pay attention to fuzzy matches (messages after `#, fuzzy`). Please be careful not to break reST notation.
 
-4. Build translated document: `make -e SPHINXOPTS="-D language='zh_CN'" html` or `sphinx-build -M html source build -D language=zh_CN`
+4. Build translated document: `make -e SPHINXOPTS="-D language='zh_CN'" html` or `sphinx-build -M html source build -D language=zh_CN`
+
+## Auto Build
+
+```bash
+pip install sphinx-autobuild
+```
+
+To autobuild the default version:
+```bash
+sphinx-autobuild source build/html
+```
+
+To autobuild the translated version:
+```bash
+sphinx-autobuild source build/html -D language=zh_CN --watch locales/zh_CN
+```
+
+By default, the doc is at `http://127.0.0.1:8000`