yaml: unify 0 stats counter config option terms

When we added feature OISF#5976 (72146b9), we overlook that we also have
a config stats option for the human-readable stats logs to output
0 counters.
Due to not seeing this before, we now have two different setting names
for basically the same thing, but in different logs:
- zero-valued-counters for EVE
- null-values for stats.log

This ensures we use the same terminology, and change the recently added
one to `null-values`, as this one has been around for longer.

Task OISF#6962

doc/userguide/output/eve/eve-json-output.rst

@@ -293,15 +293,15 @@ While the human-friendly `stats.log` output will only log out non-zeroed
 counters, by default EVE Stats logs output all enabled counters, which may lead
 to fairly verbose logs.
 
-To reduce log file size, one may set `zero-valued-counters` to false. Do note
+To reduce log file size, one may set `null-values` to false. Do note
 that this may impact on the visibility of information for which a stats counter
 as zero is relevant.
 
 Config::
 
     - stats:
         # Don't log stats counters that are zero. Default: true
-        #zero-valued-counters: false    # False will NOT log stats counters: 0
+        #null-values: false    # False will NOT log stats counters: 0
 
 Date modifiers in filename
 ~~~~~~~~~~~~~~~~~~~~~~~~~~

doc/userguide/partials/eve-log.yaml

@@ -170,7 +170,7 @@ outputs:
             threads: no       # per thread stats
             deltas: no        # include delta values
             # Don't log stats counters that are zero. Default: true
-            #zero-valued-counters: false    # False will NOT log stats counters: 0
+            #null-values: false    # False will NOT log stats counters: 0
         - dhcp:
             # DHCP logging.
             enabled: yes

src/output-json-stats.c

@@ -450,7 +450,7 @@ static OutputInitResult OutputStatsLogInitSub(ConfNode *conf, OutputCtx *parent_
         const char *totals = ConfNodeLookupChildValue(conf, "totals");
         const char *threads = ConfNodeLookupChildValue(conf, "threads");
         const char *deltas = ConfNodeLookupChildValue(conf, "deltas");
-        const char *zero_counters = ConfNodeLookupChildValue(conf, "zero-valued-counters");
+        const char *zero_counters = ConfNodeLookupChildValue(conf, "null-values");
         SCLogDebug("totals %s threads %s deltas %s", totals, threads, deltas);
 
         if ((totals != NULL && ConfValIsFalse(totals)) &&

suricata.yaml.in

@@ -319,7 +319,7 @@ outputs:
             threads: no       # per thread stats
             deltas: no        # include delta values
             # Don't log stats counters that are zero. Default: true
-            #zero-valued-counters: false    # False will NOT log stats counters: 0
+            #null-values: false    # False will NOT log stats counters: 0
         # bi-directional flows
         - flow
         # uni-directional flows