The block conversion changed the bodies of the reference sections but
left every "**Syntax:**" header spelling the line-based format, so each
page opened by teaching the format it then stopped using. Six files
were missed entirely: runparts, files, capabilities, requirements,
runlevels, and switchroot.
runparts had no block spelling written down anywhere, though the parser
has read `runparts`, `runparts-progress`, and `runparts-sysv` all along.
tty gains a table per variant. Its three syntax lines carried nine
positional fields between them, which no longer describes anything the
parser accepts.
Fixes#148
Signed-off-by: Joachim Wiberg <troglobit@gmail.com>