Relocate docs/ --> doc/, like most other projects have

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

src/service.c

@@ -827,7 +827,8 @@ static void parse_cmdline_args(svc_t *svc, char *cmd)
  *
  * Service conditions can be: svc/<PATH> for PID files, net/<IFNAME>/up
  * and net/<IFNAME>/exists.  The condition handling is further described
- * docs/conditions.md.
+ * in doc/conditions.md, but worth mentioning here is that the condition
+ * name itself can be modified using the :ID and name:foo syntax.
  *
  * For multiple instances of the same command, e.g. multiple DHCP
  * clients, the user must enter an ID, using the :ID syntax.