[docs] Typofix in prerequisites.md

"yo" -> "to" & drop duplicate "use"

Author: demon

docs/book/src/topics/prerequisites.md

@@ -61,7 +61,7 @@ To create and manage clusters, this infrastructure provider uses a service accou
 
 From your cloud console, follow [these instructions](https://cloud.google.com/iam/docs/creating-managing-service-accounts#creating) to create a new service account with `Editor` permissions.
 
-If you plan yo use GKE the the service account will also need the `iam.serviceAccountTokenCreator` role.
+If you plan to use GKE the service account will also need the `iam.serviceAccountTokenCreator` role.
 
 Afterwards, generate a JSON Key and store it somewhere safe.