Add mamba recommendation into docs (OSOceanAcoustics#1084)

* add mamba into installation guide

* update dev env guide, revise language re libmamba

* tweak wording

docs/source/contributing.rst

@@ -72,12 +72,20 @@ then set the source repository as the ``upstream`` git remote:
     cd echopype
     git remote add upstream https://github.com/OSOceanAcoustics/echopype.git
 
-Create a `conda <https://docs.conda.io>`_ environment for echopype development
-(replace the Python version with your preferred version):
+Below shows the steps to create a `conda <https://docs.conda.io>`_
+environment for echopype development
+(replace the Python version with your preferred version).
+
+.. attention::
+    We recommend using the ``libmamba`` solver instead of the classic solver,
+    since the ``conda create`` and ``conda install`` step could take very long or fail.
+    See instructions `here <https://conda.github.io/conda-libmamba-solver/getting-started/>`_
+    for installation and usage.
+
 
 .. code-block:: bash
 
-    # create conda environment using the supplied requirements files
+    # create a conda environment using the supplied requirements files
     # note the last one docs/requirements.txt is only required for building docs
     conda create -c conda-forge -n echopype --yes python=3.9 --file requirements.txt --file requirements-dev.txt --file docs/requirements.txt
 
@@ -93,13 +101,6 @@ Create a `conda <https://docs.conda.io>`_ environment for echopype development
     # the command will install all the dependencies along with plotting dependencies.
     pip install -e ".[plot]"
 
-.. note::
-
-    Try using `mamba <https://mamba.readthedocs.io>`_ instead of ``conda``
-    if the ``conda create`` and ``conda install`` step fail or take too long.
-    ``Mamba`` is a drop-in replacement for conda environment creation and package
-    installation that is typically faster than conda.
-
 See the :doc:`installation` page to simply install the latest echopype release from conda or PyPI.
 
 

docs/source/installation.rst

@@ -18,6 +18,11 @@ or through conda from the `conda-forge Anaconda channel <https://anaconda.org/co
 
    $ conda install -c conda-forge echopype
 
+.. attention::
+   We recommend using the ``libmamba`` solver instead of the classic solver.
+   See instructions `here <https://conda.github.io/conda-libmamba-solver/getting-started/>`_
+   for installation and usage.
+
 Previous releases are also available on PyPI and conda.
 
 For instructions on installing a development version of echopype,