docs: Update plot docs (ecmwf#327)

Author: HCookie

docs/inference/configs/outputs.rst

@@ -90,18 +90,12 @@ Each state variable is written in its own Zarr array.
 
 The ``plot`` output writes the output to a series of plots. The plots
 are produced in a directory, and the file are name according to a
-template. Dates are formatted using the `strftime` function before being
-used by the template. You can select which variables to plot.
+template. They are produced with `earthkit-plots`. You can specify which
+variables are plotted, and the domain to be shown.
 
 .. literalinclude:: yaml/outputs_4.yaml
    :language: yaml
 
-.. warning::
-
-   This feature is experimental and is not yet fully implemented. The
-   plot generated are very basic and are intended for debugging
-   purposes. This feature will be developed further.
-
 *****
  raw
 *****

docs/inference/configs/yaml/outputs_4.yaml

@@ -2,6 +2,7 @@ output:
   plot:
     path: /path/to/directory
     format: png
-    dpi: 300
-    strftime: "%Y%m%d%H%M%S"
-    template: "plot_{variable}_{date}.{format}"
+    domain: Europe
+    variables:
+      - 2t
+      - msl