[DOC] add "changing internet connection" to list of possible fixes in FixInternet.md

[2018robert]

Please provide a clear and concise description of the changes you would like to see made to the documentation.

Documentation/Fix Guides/Post-Install Issues/FixInternet.md

I spent hours working on this.....uninstalling and reinstalling...then I found the connecting to a different wifi network resolved the lack of internet in WSA. Not sure why...but found a report here:

https://www.reddit.com/r/WSA/comments/s3ppxe/only_local_network_access_with_no_internet_access/

of someone switching from ethernet to wifi and resolving the same issue.