[master] 37f1d9241 doc: Briefly mention logexpect's '?' skip marker

[Dridi Boukelmoune]

commit 37f1d9241d91f7c3279eb5e74067732b75bd6ba1
Author: Dridi Boukelmoune <dridi.boukelmoune at gmail.com>
Date:   Wed Jan 13 08:27:18 2021 +0100

    doc: Briefly mention logexpect's '?' skip marker

diff --git a/bin/varnishtest/vtc_logexp.c b/bin/varnishtest/vtc_logexp.c
index 320bfe599..5d638c74f 100644
--- a/bin/varnishtest/vtc_logexp.c
+++ b/bin/varnishtest/vtc_logexp.c
@@ -95,7 +95,7 @@
  *
  * And the arguments of the specifications lines are:
  *
- * skip: [uint|*]
+ * skip: [uint|*|?]
  *         Max number of record to skip
  *
  * vxid: [uint|*|=]
@@ -108,7 +108,9 @@
  *         regular expression to match against (optional)
  *
  * For skip, vxid and tag, '*' matches anything, '=' expects the value of the
- * previous matched record.
+ * previous matched record. The '?' marker is equivalent to zero, expecting a
+ * match on the next record. The difference is that '?' can be used when the
+ * order of individual consecutive logs is not deterministic.
  */
 
 #include "config.h"