doc: convert the documentation to the block format

The syntax overview no longer describes a line-based format, since that
is not what the rest of the documentation shows.  It now covers the
grammar, the two naming conventions, the nine aliases, and the leading
'-' on a path, and it says plainly that both formats are still read and
told apart per file by content.  Without that, a reader with an
existing configuration is left wondering what happened to it.

service-opts.md was a list of modifiers to place between a directive
and its command, so it needed rewriting rather than translating: there
are no positions left to describe.  It is now grouped by what the
settings do.

conditions.md needed correcting.  It presented '!' as a condition
prefix alongside '~'.  It is neither a condition nor a negation, it is
a flag on the block that means one thing on a service and another on a
run or task, so it is spelled reload-signal and required here, and the
page maps the old form to both.

Two things the pages claimed are not true.  The kill delay range is
1-300, not 1-60, and stop and reload scripts are no longer run without
a timeout.

ChangeLog.md keeps its line-based examples.  Those sit in historical
release entries, and rewriting them in a syntax that did not exist at
the time would misdate the format.

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

doc/config/service-sync.md

@@ -38,10 +38,10 @@ This will be made the default in Finit 5.0.  In this mode of operation,
 every service needs to explicitly declare their readiness notification,
 like this:
 
-    service notify:pid     watchdogd
-    service notify:systemd foo
-    service notify:s6      bar
-    service notify:none    qux
+    service watchdogd { notify = "pid"      command = "watchdogd" }
+    service foo       { notify = "systemd"  command = "foo"       }
+    service bar       { notify = "s6"       command = "bar"       }
+    service qux       { notify = "none"     command = "qux"       }
 
 The `notify:none` syntax is for completeness in systems which run in
 `readiness pid` mode (default).  Services declared with `notify:none`
@@ -50,8 +50,15 @@ will transition to ready as soon as Finit has started them, e.g.,
 
 To synchronize two services the following condition can be used:
 
-    service notify:pid                 watchdogd
-    service <service/watchdogd/ready>  stress-ng --cpu 8
+    service watchdogd {
+        notify  = "pid"
+        command = "watchdogd"
+    }
+
+    service stress-ng {
+        conditions = { "service/watchdogd/ready" }
+        command    = "stress-ng --cpu 8"
+    }
 
 For details on the syntax and options, see below.