fix typo, 'action.config' should be 'actions.config'

Change I475f152bc1 made 'actions.config' the proper name for an its
rules configuration file but didn't update the doc to reflect it.
This change brings the doc up to date with that change.

Change-Id: I44b68ca775603752b6566f381f59cad16c2f84ee
diff --git a/src/main/resources/Documentation/config-rulebase-common.md b/src/main/resources/Documentation/config-rulebase-common.md
index 59a12bd..4712e31 100644
--- a/src/main/resources/Documentation/config-rulebase-common.md
+++ b/src/main/resources/Documentation/config-rulebase-common.md
@@ -44,7 +44,7 @@
 Goodness! Someone gave a negative code review in Gerrit on an
 associated change.” to each such issue.
 
-The order of rules in `etc/its/action.config` need not be
+The order of rules in `etc/its/actions.config` need not be
 respected. So in the above example, do not rely on `rule1` being
 evaluated before `rule2`.
 
@@ -591,4 +591,4 @@
 
 [Back to @PLUGIN@ documentation index][index]
 
-[index]: index.html
\ No newline at end of file
+[index]: index.html