Rename tk binary to gotk

To avoid conflicts with the `tk` binary from the Tanka project.

docs/cmd/gotk_create_source.md

@@ -0,0 +1,31 @@
+## gotk create source
+
+Create or update sources
+
+### Synopsis
+
+The create source sub-commands generate sources.
+
+### Options
+
+```
+  -h, --help   help for source
+```
+
+### Options inherited from parent commands
+
+```
+      --export              export in YAML format to stdout
+      --interval duration   source sync interval (default 1m0s)
+      --kubeconfig string   path to the kubeconfig file (default "~/.kube/config")
+      --namespace string    the namespace scope for this operation (default "gitops-system")
+      --timeout duration    timeout for this operation (default 5m0s)
+      --verbose             print generated objects
+```
+
+### SEE ALSO
+
+* [gotk create](gotk_create.md)	 - Create or update sources and resources
+* [gotk create source git](gotk_create_source_git.md)	 - Create or update a GitRepository source
+* [gotk create source helm](gotk_create_source_helm.md)	 - Create or update a HelmRepository source
+