DOC: update Anaconda download link

doc/installation.ipynb

@@ -27,7 +27,7 @@
     "(e.g. with\n",
     "[Miniforge](https://github.com/conda-forge/miniforge),\n",
     "[Miniconda](https://docs.conda.io/en/latest/miniconda.html) or\n",
-    "[Anaconda](https://www.anaconda.com/products/distribution#Downloads)),\n",
+    "[Anaconda](https://www.anaconda.com/download#downloads)),\n",
     "you can install `nbsphinx` from the [conda-forge](https://conda-forge.org/) channel:\n",
     "\n",
     "    conda install -c conda-forge nbsphinx\n",
@@ -60,7 +60,7 @@
     "\n",
     "Of course you'll need Python, because both Sphinx and `nbsphinx` are implemented in Python.\n",
     "There are many ways to get Python.\n",
-    "If you don't know which one is best for you, you can try [Anaconda](https://www.anaconda.com/products/individual#Downloads).\n",
+    "If you don't know which one is best for you, you can try [Miniforge/Mambaforge](https://github.com/conda-forge/miniforge).\n",
     "\n",
     "### Sphinx\n",
     "\n",