Fix whats-new for 0.15 (#3723)

* Fix whats-new for 0.15

* fix plot.

* fix CFTimeIndex

* fix map_blocks

* more fix

* Update doc/whats-new.rst

Co-Authored-By: keewis <[email protected]>

* Update doc/whats-new.rst

Co-Authored-By: keewis <[email protected]>

* more fixes.

* fix the docstring of step

* Add weather-data example.

* Add release note

* more fixes.

* reference the headings inside the example notebook

* lint fixes

* more fixes

Co-authored-by: keewis <[email protected]>

Author: dcherian

doc/api.rst

@@ -649,6 +649,7 @@ Plotting
    plot.imshow
    plot.line
    plot.pcolormesh
+   plot.step
    plot.FacetGrid
 
 Faceting