Previously, there was a two similar sections in `marking messages as read`.
We want to move the intro paragraph from the second section to the first
section. Then drop the "Do not mark as read" section altogether.
These files are not Jinja2 templates, so there's no reason that they needed
to be inside `templates/zerver`. Moving them to the top level reflects their
importance and also makes it feel nicer to work on editing the help center content,
without it being unnecessary buried deep in the codebase.
David Rosa
Joelute
Lauryn Menard