🔧 Add notfound extension

Author: veit

docs/404.rst

@@ -0,0 +1,8 @@
+==============
+Page not found
+==============
+
+This page may have been moved.
+
+Please select a page from the side menu or visit our homepage at
+https://python-basics-tutorial.readthedocs.io/en/latest/.

docs/conf.py

@@ -40,16 +40,18 @@
 # extensions coming with Sphinx (named "sphinx.ext.*") or your custom ones.
 extensions = [
     "nbsphinx",
+    "notfound.extension",
     "pygments_pytest",
     "sphinx.ext.autodoc",
-    "sphinx.ext.viewcode",
     "sphinx.ext.graphviz",
     "sphinx.ext.intersphinx",
-    "sphinxcontrib.plantuml",
-    "sphinxcontrib.cairosvgconverter",
-    "sphinxext.opengraph",
+    "sphinx.ext.intersphinx",
+    "sphinx.ext.viewcode",
     "sphinx_copybutton",
     "sphinx_inline_tabs",
+    "sphinxcontrib.cairosvgconverter",
+    "sphinxcontrib.plantuml",
+    "sphinxext.opengraph",
 ]
 
 plantuml = "plantuml"

pyproject.toml

@@ -19,15 +19,16 @@ docs = [
     "furo",
     "ipython",
     "ipywidgets",
+    "matplotlib", # matplotlib is required for social cards
     "nbsphinx",
-    "sphinxext.opengraph", # matplotlib is required for social cards
-    "matplotlib",
-    "sphinx_copybutton",
+    "pygments-pytest",
     "sphinx-inline-tabs",
-    "sphinxcontrib.plantuml",
-    "sphinxcontrib-svg2pdfconverter",
     "sphinx-lint",
-    "pygments-pytest",
+    "sphinx-notfound-page",
+    "sphinx_copybutton",
+    "sphinxcontrib-svg2pdfconverter",
+    "sphinxcontrib.plantuml",
+    "sphinxext.opengraph",
 ]
 
 dev = [