[DOC] fix ignore-persist/force-persist documentation

Shame on me, I didn't correctly document the "ignore-persist" statement
(convinced I used it like this in my tests, which is not the case at all...)
This fixes the doc and updates the proxy keyword matrix to add "force-persist".

doc/configuration.txt

@@ -805,12 +805,14 @@ errorloc                                  X          X         X         X
 errorloc302                               X          X         X         X
 -- keyword -------------------------- defaults - frontend - listen -- backend -
 errorloc303                               X          X         X         X
+force-persist                             -          X         X         X
 fullconn                                  X          -         X         X
 grace                                     X          X         X         X
 hash-type                                 X          -         X         X
 http-check disable-on-404                 X          -         X         X
 http-request                              -          X         X         X
 id                                        -          X         X         X
+ignore-persist                            -          X         X         X
 log                                       X          X         X         X
 maxconn                                   X          X         X         -
 mode                                      X          X         X         X
@@ -836,7 +838,6 @@ option httpchk                            X          -         X         X
 option httpclose                     (*)  X          X         X         X
 option httplog                            X          X         X         X
 option http_proxy                    (*)  X          X         X         X
-option ignore-persist                     -          X         X         X
 option independant-streams           (*)  X          X         X         X
 option log-health-checks             (*)  X          -         X         X
 option log-separate-errors           (*)  X          X         X         -
@@ -1005,7 +1006,7 @@ appsession <cookie> len <length> timeout <holdtime>
         appsession JSESSIONID len 52 timeout 3h
 
   See also : "cookie", "capture cookie", "balance", "stick", "stick-table"
-             and "option ignore-persist"
+             and "ignore-persist"
 
 
 backlog <conns>
@@ -1703,7 +1704,7 @@ cookie <name> [ rewrite | insert | prefix ] [ indirect ] [ nocache ]
         cookie SRV insert postonly indirect
 
   See also : "appsession", "balance source", "capture cookie", "server"
-             and "option ignore-persist".
+             and "ignore-persist".
 
 
 default-server [param*]
@@ -1898,7 +1899,7 @@ force-persist { if | unless } <condition>
   "unless" condition is met. The final redispatch is always disabled when this
   is used.
 
-  See also : "option redispatch", "option ignore-persist", "persist",
+  See also : "option redispatch", "ignore-persist", "persist",
              and section 7 about ACL usage.
 
 
@@ -2091,6 +2092,30 @@ id <value>
   value will be 1. This ID is currently only returned in statistics.
 
 
+ignore-persist { if | unless } <condition>
+  Declare a condition to ignore persistence
+  May be used in sections:    defaults | frontend | listen | backend
+                                  no   |    yes   |   yes  |   yes
+
+  By default, when cookie persistence is enabled, every requests containing
+  the cookie are unconditionally persistent (assuming the target server is up
+  and running).
+
+  The "ignore-persist" statement allows one to declare various ACL-based
+  conditions which, when met, will cause a request to ignore persistence.
+  This is sometimes useful to load balance requests for static files, which
+  oftenly don't require persistence. This can also be used to fully disable
+  persistence for a specific User-Agent (for example, some web crawler bots).
+
+  Combined with "appsession", it can also help reduce HAProxy memory usage, as
+  the appsession table won't grow if persistence is ignored.
+
+  The persistence is ignored when an "if" condition is met, or unless an
+  "unless" condition is met.
+
+  See also : "force-persist", "cookie", and section 7 about ACL usage.
+
+
 log global
 log <address> <facility> [<level> [<minlevel>]]
   Enable per-instance logging of events and traffic.