Merging to release-5.2: [DX-1094] Update session_lifetime description…

… to mention that it is a UNIX timestamp (#4327)

[DX-1094] Update session_lifetime description to mention that it is a UNIX timestamp (#4327)

* update session_lifetime
* Update session lifetime decription to mention that it is a UNIX timestamp
* Update linked page link title for session_lifetime
---------

Co-authored-by: Simon Pears <[email protected]>

tyk-docs/content/plugins/supported-languages/rich-plugins/rich-plugins-data-structures.md

@@ -243,7 +243,6 @@ The policy ID that is bound to this token.
 Although `apply_policy_id` is still supported, it is now deprecated. `apply_policies` is now used to list your policy IDs as an array. This supports the **[Multiple Policy]({{< ref "basic-config-and-security/security/security-policies/partitioned-policies#a-name-multiple-a-multiple-policies" >}})** feature introduced in the  **v2.4 - 1.4** release.
 {{< /note >}}
 
-
 `data_expires`
 A value, in seconds, that defines when data generated by this token expires in the analytics DB (must be using Pro edition and MongoDB).
 
@@ -266,7 +265,8 @@ As of v2.1, an Alias offers a way to identify a token in a more human-readable m
 See [Auth Plugins]({{< ref "plugins/plugin-types/auth-plugins/auth-plugins" >}}) for additional information.
 
 `session_lifetime`
-Overrides the global session lifetime, see [Physical Token Expiry]({{< ref "basic-config-and-security/security/authentication-authorization/physical-key-expiry" >}}) for additional information.
+UNIX timestamp that denotes when the key will automatically expire. Any·subsequent API request made using the key will be rejected. Overrides the global session lifetime. See [Key Expiry and Deletion]({{< ref "basic-config-and-security/security/authentication-authorization/physical-key-expiry" >}}) for more information.
+
 
 ### ResponseObject (coprocess_response_object.proto)