fix sphinx warnings (#4199)

* fix a link

* remove the earlier attempts to document .str and .dt

* fail warnings on RTD

* disable fail_on_warning again

Author: keewis

doc/api.rst

@@ -360,7 +360,6 @@ Computation
    DataArray.rolling_exp
    DataArray.weighted
    DataArray.coarsen
-   DataArray.dt
    DataArray.resample
    DataArray.get_axis_num
    DataArray.diff
@@ -369,7 +368,6 @@ Computation
    DataArray.differentiate
    DataArray.integrate
    DataArray.polyfit
-   DataArray.str
    DataArray.map_blocks
 
 

doc/whats-new.rst

@@ -59,7 +59,7 @@ Enhancements
   coordinate attributes (:pull:`4103`). By `Oriol Abril <https://github.com/OriolAbril>`_.
 - Axes kwargs such as ``facecolor`` can now be passed to :py:meth:`DataArray.plot` in ``subplot_kws``.
   This works for both single axes plots and FacetGrid plots.
-  By `Raphael Dussin <https://github.com/raphaeldussin`_.
+  By `Raphael Dussin <https://github.com/raphaeldussin>`_.
 
 New Features
 ~~~~~~~~~~~~

readthedocs.yml

@@ -6,4 +6,7 @@ build:
 conda:
     environment: ci/requirements/doc.yml
 
+sphinx:
+  fail_on_warning: false
+
 formats: []