[skip-ci] Reorganize the Plotting section of API Reference (#6732)

One top level heading with Dataset, DataArray, and Faceting subsections.

Author: dcherian

doc/api.rst

@@ -246,17 +246,6 @@ Reshaping and reorganizing
    Dataset.sortby
    Dataset.broadcast_like
 
-Plotting
---------
-
-.. autosummary::
-   :toctree: generated/
-   :template: autosummary/accessor_method.rst
-
-   Dataset.plot.scatter
-   Dataset.plot.quiver
-   Dataset.plot.streamplot
-
 DataArray
 =========
 
@@ -591,28 +580,6 @@ Reshaping and reorganizing
    DataArray.sortby
    DataArray.broadcast_like
 
-Plotting
---------
-
-.. autosummary::
-   :toctree: generated/
-   :template: autosummary/accessor_callable.rst
-
-   DataArray.plot
-
-.. autosummary::
-   :toctree: generated/
-   :template: autosummary/accessor_method.rst
-
-   DataArray.plot.contourf
-   DataArray.plot.contour
-   DataArray.plot.hist
-   DataArray.plot.imshow
-   DataArray.plot.line
-   DataArray.plot.pcolormesh
-   DataArray.plot.step
-   DataArray.plot.surface
-
 IO / Conversion
 ===============
 
@@ -687,6 +654,64 @@ Coordinates objects
    core.coordinates.DataArrayCoordinates
    core.coordinates.DatasetCoordinates
 
+Plotting
+========
+
+Dataset
+-------
+
+.. autosummary::
+   :toctree: generated/
+   :template: autosummary/accessor_method.rst
+
+   Dataset.plot.scatter
+   Dataset.plot.quiver
+   Dataset.plot.streamplot
+
+DataArray
+---------
+
+.. autosummary::
+   :toctree: generated/
+   :template: autosummary/accessor_callable.rst
+
+   DataArray.plot
+
+.. autosummary::
+   :toctree: generated/
+   :template: autosummary/accessor_method.rst
+
+   DataArray.plot.contourf
+   DataArray.plot.contour
+   DataArray.plot.hist
+   DataArray.plot.imshow
+   DataArray.plot.line
+   DataArray.plot.pcolormesh
+   DataArray.plot.step
+   DataArray.plot.surface
+
+
+Faceting
+--------
+.. autosummary::
+   :toctree: generated/
+
+   plot.FacetGrid
+   plot.FacetGrid.add_colorbar
+   plot.FacetGrid.add_legend
+   plot.FacetGrid.add_quiverkey
+   plot.FacetGrid.map
+   plot.FacetGrid.map_dataarray
+   plot.FacetGrid.map_dataarray_line
+   plot.FacetGrid.map_dataset
+   plot.FacetGrid.set_axis_labels
+   plot.FacetGrid.set_ticks
+   plot.FacetGrid.set_titles
+   plot.FacetGrid.set_xlabels
+   plot.FacetGrid.set_ylabels
+
+
+
 GroupBy objects
 ===============
 
@@ -1000,25 +1025,6 @@ Creating custom indexes
    date_range
    date_range_like
 
-Faceting
---------
-.. autosummary::
-   :toctree: generated/
-
-   plot.FacetGrid
-   plot.FacetGrid.add_colorbar
-   plot.FacetGrid.add_legend
-   plot.FacetGrid.add_quiverkey
-   plot.FacetGrid.map
-   plot.FacetGrid.map_dataarray
-   plot.FacetGrid.map_dataarray_line
-   plot.FacetGrid.map_dataset
-   plot.FacetGrid.set_axis_labels
-   plot.FacetGrid.set_ticks
-   plot.FacetGrid.set_titles
-   plot.FacetGrid.set_xlabels
-   plot.FacetGrid.set_ylabels
-
 Tutorial
 ========