DOC: config: mention clearer that the cache's total-max-size is mandatory

As reported in GH issue #3201, it's easy to overlook this, so let's make
it clearer by mentioning the keyword. This can be backported to all
versions.

diff --git a/doc/configuration.txt b/doc/configuration.txt
index 016941bdb500807113b3834a83f593685f43aa0a..b0fe209e0762ecf846185f4b738f97a54aa57a0a 100644 (file)
--- a/doc/configuration.txt
+++ b/doc/configuration.txt
@@ -19671,7 +19671,7 @@ the corresponding http-request and http-response actions.
 
 cache <name>
   Declare a cache section, allocate a shared cache memory named <name>, the
-  size of cache is mandatory.
+  size of cache is mandatory (see keyword "total-max-size" below).
 
 total-max-size <megabytes>
   Define the size in RAM of the cache in megabytes. This size is split in