Error displaying widget: model not found

まだ誰も着手していません。

## Describe the issue

```
%matplotlib widget
import matplotlib.pyplot as plt

plt.plot([0,1],[0,1])
```

results in

```
Error displaying widget: model not found
```

The javascript console shows:

```
Could not instantiate widget
Error: Could not create a model.
Uncaught (in promise) Error: Module jupyter-matplotlib, semver range ^0.10.5 is not registered as a widget module
```

## Versions

```
3.9.12 (main, Mar 26 2022, 15:44:31)
[Clang 13.1.6 (clang-1316.0.21.2)]
ipympl version: 0.8.8
Selected Jupyter core packages...
IPython : 8.2.0
ipykernel : 6.12.1
ipywidgets : 7.7.0
jupyter_client : 7.2.1
jupyter_core : 4.9.2
jupyter_server : 1.16.0
jupyterlab : 3.3.2
nbclient : 0.5.13
nbconvert : 6.4.5
nbformat : 5.3.0
notebook : 6.4.10
qtconsole : not installed
traitlets : 5.1.1
Known nbextensions:
config dir: /Users/remco/.jupyter/nbconfig
notebook section
toggle_all_line_numbers/main enabled
- Validating: OK
equation-numbering/main enabled
- Validating: OK
toc2/main enabled
- Validating: OK
collapsible_headings/main disabled
nbextensions_configurator/config_menu/main enabled
- Validating: problems found:
- require? X nbextensions_configurator/config_menu/main
scroll_down/main enabled
- Validating: OK
jupyter-js-widgets/extension enabled
- Validating: OK
contrib_nbextensions_help_item/main enabled
- Validating: OK
tree section
nbextensions_configurator/tree_tab/main enabled
- Validating: problems found:
- require? X nbextensions_configurator/tree_tab/main
config dir: /usr/local/etc/jupyter/nbconfig
notebook section
jupyter-matplotlib/extension enabled
- Validating: OK
jupyter-js-widgets/extension enabled
- Validating: OK
JupyterLab v3.3.2
/usr/local/share/jupyter/labextensions
jupyter-matplotlib v0.10.1 enabled OK
@jupyter-widgets/jupyterlab-manager v3.0.1 enabled OK (python, jupyterlab_widgets)

Other labextensions (built into JupyterLab)
app dir: /opt/homebrew/Cellar/python@3.9/3.9.12/Frameworks/Python.framework/Versions/3.9/share/jupyter/lab

The following source extensions are overshadowed by older prebuilt extensions:
jupyter-matplotlib
```

まず notebook のスニペットを再現し、JupyterLab の拡張機能一覧を確認します。ipympl 0.8.8 と jupyter-matplotlib v0.10.1 拡張機能を比較し、特に古い拡張機能がそれを隠しているという報告を確認します。model または unregistered-module エラーなしでウィジェットが表示されれば完了です。

索引モデルが issue の本文から書いたものです。