DOC: move the "group" keyword at the right place

It looks like "hard-stop-after", "h1-case-adjust" and "h1-case-adjust-file"
were added before "group", breaking alphabetical ordering.
diff --git a/doc/configuration.txt b/doc/configuration.txt
index 7cf43d4..eadf1f3 100644
--- a/doc/configuration.txt
+++ b/doc/configuration.txt
@@ -834,6 +834,10 @@
   will only be able to drop these groups if started with superuser privileges.
   See also "group" and "uid".
 
+group <group name>
+  Similar to "gid" but uses the GID of group name <group name> from /etc/group.
+  See also "gid" and "user".
+
 hard-stop-after <time>
   Defines the maximum time allowed to perform a clean soft-stop.
 
@@ -899,10 +903,6 @@
   See "h1-case-adjust", "option h1-case-adjust-bogus-client" and
   "option h1-case-adjust-bogus-server".
 
-group <group name>
-  Similar to "gid" but uses the GID of group name <group name> from /etc/group.
-  See also "gid" and "user".
-
 log <address> [len <length>] [format <format>] [sample <ranges>:<smp_size>]
     <facility> [max level [min level]]
   Adds a global syslog server. Several global servers can be defined. They