In commit f3a67f0e31, we updated the documented search filters
for direct messages, but these had not been changed in the backend
or the frontend of the codebase and therefore the newly documented
filters do not work. Reverts the documentation to the previous
search filters.
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.
Alya Abbott
Lauryn Menard
David Rosa
Lauryn Menard