mrkd started enforcing the `name -- short description` style of top-level
headings somewhere, and was thus failing to build the man-pages. I swapped
the title and with the existing short description to make it work
again. `mrkd` will automatically infer the section from the filename so no
need to put it in the title as well.
In addition I removed the "last updated" lines at the bottom since they are
out of date at best, and misleading at the worst. If we want to keep them, I'd
suggest generating them from the commit that last touched them.
This is to future-proof against multi-part-payments: the low-level commands
will start returning multiple results once we have that, so prepare
transition plan now.
Closes: #2372
Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
