remove/replace broken links

[paddymul]

fixes some broken links from CI

I saw these from my last run

=================================== FAILURES ===================================
_ /home/runner/work/accessibility/accessibility/docs/community/meeting-minutes/jupyterlab-accessibility-meetings/all-minutes.md: https://imgur.com/a/6HvOcYK _
https://imgur.com/a/6HvOcYK: 429: Unknown Error
_ /home/runner/work/accessibility/accessibility/docs/community/meeting-minutes/jupyterlab-accessibility-meetings/all-minutes.md: http://bofh.nikhef.nl/events/FOSDEM/2021/D.javascript/codemirror.webm _
http://bofh.nikhef.nl/events/FOSDEM/2021/D.javascript/codemirror.webm: 404: Not Found
_ /home/runner/work/accessibility/accessibility/docs/community/meeting-minutes/jupyterlab-accessibility-meetings/all-minutes.md: https://technica11y.org/designing-and-coding-for-low-vision _
https://technica11y.org/designing-and-coding-for-low-vision: 522: 
_ /home/runner/work/accessibility/accessibility/docs/community/meeting-minutes/jupyterlab-accessibility-meetings/all-minutes.md: https://i.imgur.com/aKRjl2E.png _
https://i.imgur.com/aKRjl2E.png: 429: Unknown Error

The imgur links seem to work occasionally. the technica11y link and the codemirror video were failures. I found a replacement for the codemirror video

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:books: Documentation preview :books:: https://jupyter-accessibility--129.org.readthedocs.build/en/129/

[trallard]

Thank you, will merge and will need to keep an eye on those imgur links