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/logging.md

@@ -3,8 +3,8 @@ General Logging
 
 **Syntax:** `log { size = 200k  count = 5 }`
 
-Log rotation for run/task/services using the `log` sub-option with
-redirection to a log file.  Global setting, applies to all services.
+Log rotation for run/task/services that redirect output to a log file
+with their own `log` block.  Global setting, applies to all services.
 
 The size can be given as bytes, without a specifier, or in `k`, `M`,
 or `G`, e.g. `size = 10M`, or `size = 3G`.  A value of `size = 0` disables
@@ -17,22 +17,30 @@ size limit is reached.
 Redirecting Output
 ------------------
 
-The `run`, `task`, and `service` stanzas also allow the keyword `log` to
-redirect `stderr` and `stdout` of the application to a file or syslog
+The `run`, `task`, and `service` blocks take a `log` block of their own,
+redirecting `stderr` and `stdout` of the application to a file or syslog
 using the native `logit` tool.  This is useful for programs that do not
 support syslog on their own, which is sometimes the case when running
 in the foreground.
 
-The full syntax is:
+An empty block means syslog with the defaults, and three keys adjust it:
 
-    log:/path/to/file
-    log:prio:facility.level,tag:ident
-    log:console
-    log:null
-    log
+| Setting | Description |
+|---|---|
+| `file` | Write to this path instead of syslog |
+| `priority` | Syslog `facility.level`, default `daemon.info` |
+| `identity` | Syslog tag, default the basename of the command |
 
-Default `prio` is `daemon.info` and default `tag` is the basename of the
-service or run/task command.
+`/dev/console` and `/dev/null` are spelled as the paths they are:
+
+    service foo { log { }                       command = "foo" }  # syslog
+    service foo { log { file = "/var/log/foo" } command = "foo" }  # a file
+    service foo { log { file = "/dev/console" } command = "foo" }  # console
+    service foo { log { file = "/dev/null" }    command = "foo" }  # discard
+
+> [!NOTE]
+> A `log` block at file scope is a different setting -- that one is the
+> global rotation above, and it takes only `size` and `count`.
 
 Log rotation is controlled using the global `log` setting.