Inconsistent docs for number of operational modes

[lindhe]

In the docs, it says that there are 3 operational modes but lists four:

grafana-operator/docs/docs/grafana.md

Lines 21 to 31 in ffdc532

	To support that, we offer 3 operational modes (you can switch between those through `WATCH_NAMESPACE` environment variable):
	- cluster-wide (`WATCH_NAMESPACE: ""`);
	- multiple namespaces (`WATCH_NAMESPACE: "grafana, foo"`):
	- Cluster-wide permissions are still required;
	- single namespace (`WATCH_NAMESPACE: "grafana"`):
	- With this mode, it's possible to use `Role` + `RoleBinding` to grant the operator the required access.
	- mutliple namespaces using label selector (`WATCH_NAMESPACE_SELECTOR: "environment: dev"`):
	- With this mode, it is possible detect and load all namespaces that match the label selector automatically.
	New namespaces won't be automatically included until the Grafana operator is restarted.
	- Cluster-wide permissions are still required;

I'm guessing it should say "we offer 4 operational modes", but I don't know.

[theSuess]

Yeah, this changed with #1434, but we forgot to change the number. I'll update this now!