[DOCS] Merges duplicate pages for file realms (#49200)

docs/reference/high-availability/backup-and-restore-security-config.asciidoc

@@ -18,8 +18,8 @@ Security configuration information resides in two places:
 `xpack.security` namespace>> inside the `elasticsearch.yml` and
 `elasticsearch.keystore` files. In addition there are several other
 <<security-files, extra configuration files>> inside the same `ES_PATH_CONF`
-directory. These files define roles and role mappings and
+directory. These files define roles and role mappings and configure the
-<<configuring-file-realm, configure the file realm>>. Some of the
+<<file-realm,file realm>>. Some of the
 settings specify file paths to security-sensitive data, such as TLS keys and
 certificates for the HTTP client and inter-node communication and private key files for
 <<ref-saml-settings, SAML>>, <<ref-oidc-settings, OIDC>> and the

docs/reference/redirects.asciidoc

@@ -945,3 +945,7 @@ See <<ref-saml-encryption-settings>>.
 
 See <<ref-saml-ssl-settings>>. 
 
+[role="exclude",id="configuring-file-realm"]
+=== Configuring a file realm
+
+See <<file-realm-configuration>>. 

docs/reference/upgrade/reindex_upgrade.asciidoc

@@ -94,7 +94,7 @@ bin/elasticsearch-users userdel <user_name>
 ----------------------------------------------------------
 --
 
-For more information, see <<configuring-file-realm>>.
+For more information, see <<file-realm>>.
 ====
 endif::include-xpack[]
 

x-pack/docs/en/security/authentication/configuring-file-realm.asciidoc

@@ -1,8 +1,3 @@
-[role="xpack"]
-[[configuring-file-realm]]
-=== Configuring a file realm
-
-You can manage and authenticate users with the built-in `file` internal realm. 
 All the data about the users for the `file` realm is stored in two files on each 
 node in the cluster: `users` and `users_roles`. Both files are located in 
 `ES_PATH_CONF` and are read on startup.
@@ -22,8 +17,6 @@ or using a configuration management system such as Puppet or Chef).
 The `file` realm is added to the realm chain by default. You don't need to
 explicitly configure a `file` realm.
 
-For more information about file realms, see <<file-realm>>.
-
 . (Optional) Add a realm configuration to `elasticsearch.yml` under the
 `xpack.security.authc.realms.file` namespace. At a minimum, you must set 
 the realm's `order` attribute.

x-pack/docs/en/security/authentication/file-realm.asciidoc

@@ -23,5 +23,7 @@ To define users, the {security-features} provide the
 {ref}/users-command.html[users] command-line tool. This tool enables you to add
 and remove users, assign user roles, and manage user passwords.
 
-For more information, see 
+[[file-realm-configuration]]
-{ref}/configuring-file-realm.html[Configuring a file realm].
+==== Configuring a file realm
+
+include::configuring-file-realm.asciidoc[]

x-pack/docs/en/security/configuring-es.asciidoc

@@ -73,7 +73,7 @@ your subscription. For more information, see https://www.elastic.co/subscription
  
 --
 ** <<configuring-ad-realm,Active Directory realms>>
-** <<configuring-file-realm,File realms>>
+** <<file-realm,File realms>>
 ** <<configuring-kerberos-realm,Kerberos realms>>
 ** <<configuring-ldap-realm,LDAP realms>>
 ** <<native-realm,Native realms>>
@@ -146,7 +146,6 @@ include::securing-communications/enabling-cipher-suites.asciidoc[]
 include::securing-communications/separating-node-client-traffic.asciidoc[]
 
 include::authentication/configuring-active-directory-realm.asciidoc[]
-include::authentication/configuring-file-realm.asciidoc[]
 include::authentication/configuring-ldap-realm.asciidoc[]
 include::authentication/configuring-pki-realm.asciidoc[]
 include::authentication/configuring-kerberos-realm.asciidoc[]

x-pack/docs/en/security/reference/files.asciidoc

@@ -9,10 +9,10 @@ The {es} {security-features} use the following files:
 <<defining-roles>>.
 
 * `ES_PATH_CONF/elasticsearch-users` defines the users and their hashed passwords for
-  the `file` realm. See <<configuring-file-realm>>.
+  the `file` realm. See <<file-realm>>.
 
 * `ES_PATH_CONF/elasticsearch-users_roles` defines the user roles assignment for the
-  the `file` realm. See <<configuring-file-realm>>.
+  the `file` realm. See <<file-realm>>.
 
 * `ES_PATH_CONF/role_mapping.yml` defines the role assignments for a
   Distinguished Name (DN) to a role. This allows for LDAP and Active Directory