Add comments for which packages are only available via conda-forge

Author: GenevieveBuckley

setup.cfg

@@ -39,20 +39,20 @@ package_dir =
 # install_requires =
     # imageio
     # magicgui
-    # nifty
+    # nifty  # only available on conda-forge
     # numpy
     # pooch
-    # python-elf
+    # python-elf  # depends on vigra, which is only available on conda-forge
     # pytorch
     # qtpy
     # scikit-image
     # scipy
-    # segment-anything
+    # segment-anything  # depends on pytorch https://segment-anything.com/
     # torchvision
     # tqdm
-    # vigra
+    # vigra  # only available on conda-forge
     # zarr
-    # z5py
+    # z5py  # only available on conda-forge
 
 [options.extras_require]
 testing =