Issue-3499-guidelines-link

[charlottejmc]

I've replaced the TEI P5 guidelines link with another working link.

Closes #3499

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[anisa-hawes]

Thank you, @charlottejmc!

--

Hola @jenniferisasi, Olá @ericbrasiln,
Keeping you both updated on a quick fix to update our link to the TEI documentation.