add mermaid to sphinx extensions and doc dependencies

docs/source/conf.py

@@ -24,6 +24,7 @@ extensions = [
     "sphinx.ext.intersphinx",
     "sphinx.ext.napoleon",  # parameters look better than with numpydoc only
     "numpydoc",
+    "sphinxcontrib.mermaid",
 ]
 
 # autosummaries from source-files

pyproject.toml

@@ -60,6 +60,7 @@ doc = [
     "numpydoc>=1.1",
     "sphinx-design>=0.3",
     "myst-parser>=0.18",
+    "sphinxcontrib-mermaid>=0.7",
     "docutils>=0.18", # mdinclude with myst
 ]
 test = ["pytest-cov>=3"]