Update envtest.md

Fix typo

docs/book/src/reference/envtest.md

@@ -10,7 +10,7 @@ by default. `make test` is the one-stop shop for downloading the binaries, setti
 
 The make targets require `bash` to run. 
 
-## Installation in Air Gaped/disconnected environments
+## Installation in Air Gapped/disconnected environments
 If you would like to download the tarball containing the binaries, to use in a disconnected environment you can use 
 [`setup-envtest`][setup-envtest] to download the required binaries locally. There are a lot of ways to configure `setup-envtest` to avoid talking to 
 the internet you can read about them [here](https://github.com/kubernetes-sigs/controller-runtime/tree/master/tools/setup-envtest#what-if-i-dont-want-to-talk-to-the-internet). 
@@ -298,4 +298,4 @@ testEnv = &envtest.Environment{
 [setup-envtest]: https://pkg.go.dev/sigs.k8s.io/controller-runtime/tools/setup-envtest
 [cert-manager]: https://book.kubebuilder.io/cronjob-tutorial/cert-manager.html
 [sdk-e2e-sample-example]: https://github.com/operator-framework/operator-sdk/tree/master/testdata/go/v3/memcached-operator/test/e2e
-[sdk]: https://github.com/operator-framework/operator-sdk
+[sdk]: https://github.com/operator-framework/operator-sdk