doc: fix links for server actions in api guide

The section about server actions is talking about the
os-instance-actions API but linking to the server actions
section in the API reference. This retains the link to the
server actions section but changes the "for more details"
link to the actual os-instance-actions reference.

Change-Id: Icb5c4cadd1c552f44bfadefd055c07ea38df0eaa

Author: mriedem

api-guide/source/faults.rst

@@ -67,11 +67,13 @@ Response header example::
 Server Actions
 --------------
 
-There is an API for end users to list the outcome of Server Actions,
+There is an API for end users to list the outcome of `Server Actions`_,
 referencing the requested action by request id.
 
 For more details, please see:
-https://docs.openstack.org/api-ref/compute/#servers-run-an-action-servers-action
+https://docs.openstack.org/api-ref/compute/#servers-actions-servers-os-instance-actions
+
+.. _Server Actions: https://docs.openstack.org/api-ref/compute/#servers-run-an-action-servers-action
 
 Logs
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