Update link to metadata text guidelines in Dataverse style guide

[jggautier]

The Text section of the Dataverse style guide has a link to the metadata text guidelines, and that link points to a Google Doc that lets folks know where the guidelines have moved.

I think that link should be updated so that it takes folks straight to where the text guides are now.

When this gets prioritized, I wouldn't mind making a PR to change the link in the RST file (https://github.com/IQSS/dataverse/blob/develop/doc/sphinx-guides/source/style/text.rst).

[pdurbin]

I noticed this the other day. Docs get a fast track so if you want to make a PR, I'm happy to merge it, @jggautier.

[DieuwertjeBloemen]

I wanted to test out how to make a PR, so I picked up this one as something that would also be useful to fix while creating a PR and easy enough to do.