DOCS: Hint to avoid Extension error in sphinx-build (#494)

Co-authored-by: Chris Holdgraf <choldgraf@gmail.com>

docs/quickstart.md

@@ -38,10 +38,18 @@ Once you have finished authoring your content, you can now use the [sphinx-build
 sphinx-build -nW --keep-going -b html docs/ docs/_build/html
 ```
 
+
 :::{tip}
 MyST-NB is parallel-friendly, so you can also distribute the build (and execution of notebooks) over *N* processes with: `sphinx-build -j 4`
 :::
 
+```{admonition} The execution environment is the same as your Sphinx environment
+Your Sphinx build shares the same environment with the notebooks you execute during a build.
+Ensure that you call the correct `sphinx-build` command when building your documentation, or the environment needed to run the notebooks may not be correct.
+This often happens if you see an `Extension error`  in the build log, or an error from `jupyter-cache`.
+```
+
+
 :::{seealso}
 Check out [Read the Docs](https://docs.readthedocs.io) for hosting and *continuous deployment* of documentation
 :::

docs/render/hiding.md

@@ -8,7 +8,7 @@ kernelspec:
 
 You can use Jupyter Notebook **cell tags** to control some of the behavior of
 the rendered notebook.[^download]
-If you are using cell tags for the first time, you can read more about them in this tutorial https://jupyterbook.org/en/stable/content/metadata.html#add-metadata-to-notebooks
+If you are using cell tags for the first time, you can read more about them in this tutorial <https://jupyterbook.org/en/stable/content/metadata.html#add-metadata-to-notebooks>
 
 [^download]: This notebook can be downloaded as
             **{nb-download}`hiding.ipynb`** and {download}`hiding.md`