Update links after Learn rebrand

[AlexJerabek]

Thank you for your pull request. Please provide the following information.

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1. Do these changes impact User Experience? (e.g., how the user interacts with Yo Office and/or the files and folders the user sees in the project that Yo Office creates)

   • [x] Yes
   • [ ] No

   If Yes, briefly describe what is impacted.

The links to docs.microsoft.com are currently being redirected to learn.microsoft.com. This change removes the need for that redirect.

2. Do these changes impact documentation? (e.g., a tutorial on https://docs.microsoft.com/en-us/office/dev/add-ins/overview/office-add-ins)

   • [ ] Yes
   • [x] No

   If Yes, briefly describe what is impacted.

3. Validation/testing performed:

   Describe manual testing done.

4. Platforms tested:

   • [ ] Windows
   • [ ] Mac

[AlexJerabek]

Tagging @ElizabethSamuel-MSFT for awareness.

[millerds]

/Azurepipelines run

[azure-pipelines[bot]]

Azure Pipelines successfully started running 1 pipeline(s).

[AlexJerabek]

Thanks @millerds! How does this get checked in?