JS add PD newsletter link

[jenniferstruthers1-nhs]

Description

❓What: Added a link to the PD newsletter site (now open to all) to the "How you can learn data science" section. Open to changes. In the near future I think the PD team might also be interested in adding some info to the resources they offer and I think this would be a good place for it.

🧠Why?: To advertise some of the resources our team have to learn more about DS.

👨‍💻How?: By adding some text and a button to the page.

Checklist:

Have checked for the following:

• [x] The website still builds correctly, and you can view it using mkdocs serve.
• [x] There are no new "warnings" from mkdocs
• [x] Does your page follow the page template (or here in Markdown)? (need to make a new one specific to NHSE Data Science)
• [x] Spelling errors
• [x] Consistent capitalization
• [x] Consistent numbers
• [x] Material features incorrectly implemented: search for code blocks and markers (e.g. !!!).
• [x] Code snippets don't work
• [x] Images not working
• [x] Links not working

Where it was tested

• Github Codespaces - 2-core, 4GB RAM, 32GB hard drive
• devcontainer.json describes further settings

[SamHollings]

@jenniferstruthers1-nhs I made some changes to hopefully make your newsletter a bit more prominent - let me know what you think.

[jenniferstruthers1-nhs]

@SamHollings fully agree with the changes you've made! I just made one tiny edit. I'm happy for this to be merged if you are :)