DOC: management: place "show activity" at the right place

This time it seems to be me who had trouble with alphabetical ordering.
This should be backported to 1.9.
diff --git a/doc/management.txt b/doc/management.txt
index 0d3944a..9d5e3e2 100644
--- a/doc/management.txt
+++ b/doc/management.txt
@@ -1837,6 +1837,18 @@
   Decrease the CLI level of the current CLI session to user. It can't be
   increase. See also "show cli level"
 
+show activity
+  Reports some counters about internal events that will help developers and
+  more generally people who know haproxy well enough to narrow down the causes
+  of reports of abnormal behaviours. A typical example would be a properly
+  running process never sleeping and eating 100% of the CPU. The output fields
+  will be made of one line per metric, and per-thread counters on the same
+  line. These counters are 32-bit and will wrap during the process' life, which
+  is not a problem since calls to this command will typically be performed
+  twice. The fields are purposely not documented so that their exact meaning is
+  verified in the code where the counters are fed. These values are also reset
+  by the "clear counters" command.
+
 show cli sockets
   List CLI sockets. The output format is composed of 3 fields separated by
   spaces. The first field is the socket address, it can be a unix socket, a
@@ -1961,18 +1973,6 @@
   that the output format may evolve over time so this output must not be parsed
   by tools designed to be durable.
 
-show activity
-  Reports some counters about internal events that will help developers and
-  more generally people who know haproxy well enough to narrow down the causes
-  of reports of abnormal behaviours. A typical example would be a properly
-  running process never sleeping and eating 100% of the CPU. The output fields
-  will be made of one line per metric, and per-thread counters on the same
-  line. These counters are 32-bit and will wrap during the process' life, which
-  is not a problem since calls to this command will typically be performed
-  twice. The fields are purposely not documented so that their exact meaning is
-  verified in the code where the counters are fed. These values are also reset
-  by the "clear counters" command.
-
 show info [typed|json]
   Dump info about haproxy status on current process. If "typed" is passed as an
   optional argument, field numbers, names and types are emitted as well so that