Doc update (#636)

* Doc ppdate
* Added another mention of the limitations of crane.ggcr.dev

Author: muffato

docs/getting_started/developer-guide.rst

@@ -1064,6 +1064,8 @@ will exist the second time when you add recipes.
 Manually Adding Registry Entries
 --------------------------------
 
+.. _getting_started-developer-manual-registry-entries:
+
 Great! Now you have an empty registry on your filesystem that will be pushed to GitHub
 to serve as a remote. Make sure you are back on the main branch:
 
@@ -1085,7 +1087,14 @@ without any customization for executable discovery:
     Registry entry vanessa/salad was added! Before shpc install, edit:
     /tmp/my-registry/vanessa/salad/container.yaml
 
-You could then edit that file to your liking. If you want to pull the container
+You could then edit that file to your liking.
+
+Like for ``shpc update`` :ref:`getting_started-commands-update`, tags are automatically
+populated using `crane.ggcr.dev <https://crane.ggcr.dev/ls/quay.io/biocontainers/samtools>`_,
+which only returns the 50 latest tags and obviously can only access public images.
+If you see a ``crane digest`` error instead of tags, you'll have to populate the tags yourself.
+
+Executables are by default missing. If you want shpc
 to discover executables, you'll need to install guts:
 
 .. code-block:: console

docs/getting_started/user-guide.rst

@@ -422,9 +422,12 @@ For example:
     $ cd /opt/lmod/my-registry
 
 
-And then you might want to inspect :ref:`getting_started-commands-add:` to see
-how to use shpc add to generate new container.yaml files. We are working on automation
-that can make this easier, so stay tuned for updates! After that, you'll still want to
+And then you might want to inspect :ref:`getting_started-commands-add` to see
+how to use ``shpc add`` to generate new container.yaml files.
+See :ref:`getting_started-creating-filesystem-registry` for instructions on how to
+create a registry and :ref:`getting_started-developer-manual-registry-entries` to
+populate the registry with new entries.
+After that, you'll still want to
 ensure your filesystem registry is known to shpc:
 
 .. code-block:: console