Use ` instead of " to satisfy vale

Signed-off-by: Daniel Weiße <[email protected]>

docs/docs/reference/coordinator.md

@@ -3,11 +3,11 @@
 The Coordinator exposes an HTTP-REST interface, referred to as the Client API.
 
 Responses of the API follow the [JSend specification](https://github.com/omniti-labs/jsend).
-This means all endpoints return a JSON object with a `status` field that's either "success", "fail", or "error":
+This means all endpoints return a JSON object with a `status` field that's either `success`, `fail`, or `error`:
 
-* In case of "success", the response will contain a `data` field with the actual response data.
-* In case of "error", the response will contain a `message` field with an error message.
-* In case of "fail", the response may contain a `message` field with a human readable message, as well as a `data` field with additional information.
+* In case of `success`, the response will contain a `data` field with the actual response data.
+* In case of `error`, the response will contain a `message` field with an error message.
+* In case of `fail`, the response may contain a `message` field with a human readable message, as well as a `data` field with additional information.
   * "fail" is only used in API version 2, and is returned on invalid requests by the client.
 
 The Client API is used by the MarbleRun CLI and by [the MarbleRun Go SDK](https://pkg.go.dev/github.com/edgelesssys/marblerun/api) to interact with the Coordinator.
@@ -551,7 +551,7 @@ Example response:
 
 * `type` string
 
-    The type of the secret. One of "cert-ecdsa", "cert-ed25519", "cert-rsa", "symmetric-key", "plain".
+    The type of the secret. One of `cert-ecdsa`, `cert-ed25519`, `cert-rsa`, `symmetric-key`, `plain`.
 
 * `size` integer