Update docs.md (#887)
Update docs.md (#887)

Added a link in the lightbox section to solved a user experience issue. There is no mention of needing a plugin in this section of the docs. A link to the Links and Lightboxes section of the docs will help.
getgrav/grav-learn,getgrav/grav-learn,getgrav/grav-learn,getgrav/grav-learn