This aims to elaborate a bit more on the difference between these two settings, as well as explain the `http://` or `https://` prefix.
Follow-up to [15000], [19472].
Props marybaum, sabernhardt, tobifjellner, justinahinon, webcommsat, hellofromtonya, audrasjb, robinwpdeveloper, costdev, SergeyBiryukov.
Fixes#50886.
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