doc: fix back-references and stale claims left by the conversion

Reference sections kept pointing at the line-based format they no longer
document.  `sysv` and `task` sent the reader to Services for "<COND>",
the cgroups chapter opened by listing three legacy directives and then
explained further down that only two of them exist here, and the logging
chapter still gave "log:prio:facility.level,tag:ident" as the full
syntax.

Some claims were wrong independent of the format:

  - a sysv is a supervised daemon, grouped with service in
    SVC_TYPE_DAEMON, not a variation on task
  - restart-max has no upper bound of 255, or any other
  - the built-in rescue fallback runs in 12345789, not 12345
  - conditional loading quotes system/10-hotplug.conf, not
    system/hotplug.conf
  - the key spells conflicts, not conflict
  - the built-in getty no longer wants TERM last, it is a key

`if` takes either a service name or, in angle brackets, a condition,
decided in svc_ifthen().  Only the examples showed this, so it is now
said.

Terminology follows the split index.md already draws: a block is the new
format, a stanza the line-based one.

src/rescue.conf was still line-based, missed because it sits in src/
rather than system/ or contrib/.

Signed-off-by: Joachim Wiberg <troglobit@gmail.com>

doc/config/rescue.md

@@ -47,21 +47,22 @@ system administrator.
 
 The bundled default `rescue.conf` contains nothing more than:
 
-    runlevel 1
+    runlevel = 1
     tty rescue {
         runlevel = "12345"
         rescue   = true
     }
 
-The `tty` has the `rescue` option set, which works similar to the board
-bring-up tty option `notty`.  The major difference being that `sulogin`
+The `tty` block has `rescue` set, which works similar to the board
+bring-up setting `notty`.  The major difference being that `sulogin`
 is started to query for root/admin password.  If `sulogin` is not found,
 `rescue` behaves like `notty` and gives a plain root shell prompt.
 
-If Finit cannot find `/lib/finit/rescue.conf` it defaults to:
+If Finit cannot find `/lib/finit/rescue.conf` it falls back to a
+built-in equivalent, which runs in every runlevel it can:
 
     tty rescue {
-        runlevel = "12345"
+        runlevel = "12345789"
         rescue   = true
     }