Implementation of backend plotting for slice_plot (#649)

Implementation of backend plotting for `slice_plot`

---------

Co-authored-by: Tim Mensinger <[email protected]>

Author: r3kste

docs/source/how_to/how_to_slice_plot.ipynb

@@ -83,6 +83,17 @@
     "fig.show()"
    ]
   },
+  {
+   "cell_type": "markdown",
+   "metadata": {},
+   "source": [
+    ":::{note}\n",
+    "\n",
+    "For details on using other plotting backends, see [How to change the plotting backend](how_to_change_plotting_backend.ipynb).\n",
+    "\n",
+    ":::"
+   ]
+  },
   {
    "cell_type": "markdown",
    "metadata": {},

src/optimagic/deprecations.py

@@ -192,6 +192,15 @@ def throw_none_valued_batch_evaluator_warning():
     warnings.warn(msg, FutureWarning)
 
 
+def throw_make_subplot_kwargs_in_slice_plot_future_warning():
+    msg = (
+        "The `make_subplot_kwargs` argument in `slice_plot` is deprecated and will be "
+        "removed in optimagic version 0.6.0. Customization of the subplots can be done "
+        "by modifying the returned figure."
+    )
+    warnings.warn(msg, FutureWarning)
+
+
 def replace_and_warn_about_deprecated_algo_options(algo_options):
     if not isinstance(algo_options, dict):
         return algo_options