• Add <command> tag.
• Capitalize protocol names.
• Add a more meaningful description to the second tunnel example.
• Add <userinput> tags.
• Add missing POP3-port to tunnel example.
• Wrap one of the examples in an <example> tag so that this useful example shows up in the front matter "list of examples".

PR: docs/32436
Submitted by: Martin Heinen <martin@sumuk.de>