Fix typo in book
@@ -21,7 +21,7 @@ the data in fields, or in annotations). This means that using an older
API version won't cause newer data to be lost or corrupted. See the
[Kubernetes API guidelines](../TODO.md) for more information.
-You'll also hear mention of *resources* on occaison. A resource is simply
+You'll also hear mention of *resources* on occasion. A resource is simply
a use of a Kind in the API. Often, there's a one-to-one mapping between
Kinds and resources. For instance, the `pods` resource corresponds to the
`Pod` Kind. However, sometimes, the same Kind may be returned by multiple
