ARB-1390: Add GET /managed/credentials/sshkey endpoint (#333)

* Add GET /managed/credentials/sshkey endpoint

* Update example SSH key

* Update adding SSH key link

Author: nmelehan

openapi.yaml

@@ -6637,6 +6637,52 @@ paths:
       - lang: CLI
         source: >
           linode-cli managed credential-revoke 9991
+  /managed/credentials/sshkey:
+    x-linode-cli-command: managed
+    get:
+      x-linode-grant: unrestricted only
+      tags:
+      - Managed
+      summary: View Managed SSH Key
+      description: >
+        Returns the unique SSH public key assigned to your Linode account's
+        Managed service. If you [add this public key](https://linode.com/docs/platform/linode-managed/#adding-the-public-key) to a Linode on your account,
+        Linode special forces will be able to log in to the Linode with this key
+        when attempting to resolve issues.
+      operationId: viewManagedSSHKey
+      x-linode-cli-action: credential-sshkey-view
+      security:
+      - personalAccessToken: []
+      - oauth:
+        - account:read_only
+      responses:
+        '200':
+          description: The requested Managed SSH public key.
+          content:
+            application/json:
+              schema:
+                type: object
+                description: >
+                  A unique SSH public key that allows Linode's special forces
+                  to access a Managed server to respond to Issues.
+                properties:
+                  ssh_key:
+                    type: string
+                    description: >
+                      The unique SSH public key assigned to your Linode account's Managed service.
+                    example: ssh-rsa AAAAB...oD2ZQ== managedservices@linode
+                    readOnly: true
+                    x-linode-cli-display: 1
+        default:
+          $ref: '#/components/responses/ErrorResponse'
+      x-code-samples:
+      - lang: Shell
+        source: >
+          curl -H "Authorization: Bearer $TOKEN" \
+              https://api.linode.com/v4/managed/credentials/sshkey
+      - lang: CLI
+        source: >
+          linode-cli managed credential-sshkey-view
   /managed/issues:
     x-linode-cli-command: managed
     get: