Update MRs concepts, and drop all other mentions of connection details

We're considering removing connection details from XRs in v2 so for now
focus on their existence at the MR level.

Signed-off-by: Nic Cope <[email protected]>

Author: negz

content/v2.0-preview/composition/composite-resource-definitions.md

@@ -480,70 +480,6 @@ spec:
 Changing or expanding the XRD schema requires restarting the [Crossplane pod]({{<ref "../guides/pods#crossplane-pod">}}) to take effect.
 {{< /hint >}}
 
-### Manage connection secrets
-
-When a composite resource creates managed resources, Crossplane provides any
-[connection secrets]({{<ref "../managed-resources/managed-resources#writeconnectionsecrettoref">}})
-to the composite resource. This requires the creators of composite resources to
-know the secrets provided by a managed resource. In other cases, Crossplane
-administrators may not want to expose some or all the generated connection
-secrets.
-
-XRDs can define a list of 
-{{<hover label="key" line="10">}}connectionSecretKeys{{</hover>}}
-to limit what's provided to a composite resource.
-
-Crossplane only provides the keys listed in the 
-{{<hover label="key" line="10">}}connectionSecretKeys{{</hover>}} 
-to the composite resource using this XRD. Any other connection secrets aren't
-passed to the composite resource. 
-
-{{<hint "important" >}}
-The keys listed in the
-{{<hover label="key" line="10">}}connectionSecretKeys{{</hover>}} must match the 
-key names listed in the Composition's `connectionDetails`.  
-
-An XRD ignores any keys listed that aren't created by a managed resource.
-
-For more information read the 
-[Composition documentation]({{<ref "./compositions#store-connection-details">}}).
-{{< /hint >}}
-
-
-For example, an XRD passes the keys 
-{{<hover label="key" line="11">}}username{{</hover>}}, 
-{{<hover label="key" line="12">}}password{{</hover>}} and 
-{{<hover label="key" line="13">}}address{{</hover>}}.
-
-Composite resources save these in the secret defined by their
-`writeConnectionSecretToRef` field. 
-
-```yaml {label="key",copy-lines="none"}
-apiVersion: apiextensions.crossplane.io/v1
-kind: CompositeResourceDefinition
-metadata:
-  name: xdatabases.custom-api.example.org
-spec:
-  group: custom-api.example.org
-  names:
-    kind: xDatabase
-    plural: xdatabases
-  connectionSecretKeys:
-    - username
-    - password
-    - address
-  versions:
-  # Removed for brevity
-```
-
-{{<hint "warning">}}
-You can't change the `connectionSecretKeys` of an XRD. You must delete and
-recreate the XRD to change the `connectionSecretKeys`.
-{{</hint >}}
-
-For more information on connection secrets read the 
-[Connection Secrets knowledge base article]({{<ref "../managed-resources/connection-details">}}).
-
 ### Set composite resource defaults
 XRDs can set default parameters for composite resources.
 

content/v2.0-preview/composition/composite-resources.md

@@ -281,44 +281,6 @@ spec:
   # Removed for brevity
 ```
 
-### Manage connection secrets 
-
-When a composite resource creates resources, Crossplane provides any
-[connection secrets]({{<ref "../managed-resources/managed-resources#writeconnectionsecrettoref">}})
-to the composite resource.
-
-{{<hint "important" >}}
-
-A resource may only access connection secrets allowed by the XRD. By
-default XRDs provide access to all connection secrets generated by managed
-resources.  
-Read more about [managing connection secrets]({{<ref "./composite-resource-definitions#manage-connection-secrets">}})
-in the XRD documentation.
-{{< /hint >}}
-
-Use 
-{{<hover label="writesecret" line="6">}}writeConnectionSecretToRef{{</hover>}} 
-to specify where the composite resource writes their connection secrets to. 
-
-For example, this composite resource saves the connection secrets in a 
-Kubernetes secret object named
-{{<hover label="writesecret" line="7">}}my-secret{{</hover>}} in the namespace 
-{{<hover label="writesecret" line="8">}}crossplane-system{{</hover>}}.
-
-```yaml {label="writesecret",copy-lines="none"}
-apiVersion: example.org/v1alpha1
-kind: xMyDatabase
-metadata:
-  name: my-composite-resource
-spec:
-  writeConnectionSecretToRef:
-    name: my-secret
-    namespace: crossplane-system
-  # Removed for brevity
-```
-
-For more information on connection secrets read the [Connection Secrets knowledge base article]({{<ref "../managed-resources/connection-details">}}).
-
 ### Pausing composite resources
 
 <!-- vale Google.WordList = NO -->

content/v2.0-preview/guides/function-patch-and-transform.md

@@ -1833,13 +1833,10 @@ the composite resources.
 By default an XRD writes all secret keys listed in the composed resources
 `connectionDetails` to the combined secret object.
 
-Read the
-[CompositeResourceDefinition documentation]({{<ref "../composition/composite-resource-definitions#manage-connection-secrets">}})
-for more information on restricting secret keys.
-{{< /hint >}}
 
-For more information on connection secrets read the
-[Connection Secrets concepts age]({{<ref "../managed-resources/connection-details">}}).
+For more information on connection secrets read about
+[managed resources]({{<ref "../managed-resources/managed-resources#writeConnectionSecretToRef">}}).
+{{</hint>}}
 
 ## Resource readiness checks