Add short notice about this to the manual

my_switch = true

my_other_switch = 0

```

{{% alert title="Note" color="info" %}}

In some places, providing configuration variables with units is mandatory. In case the respective input should be interpreted as base units, or without units such as a weighting potential, the parameter can be provided as empty string, i.e. `observable_units = ""`.

{{% /alert %}}