DOCSP-38360 filling out snippets reference page (#333)

* DOCSP-38360 filling out snippets reference page

* DOCSP-38360 filling out snippets reference page

* DOCSP-38360 filling out snippets reference page

* DOCSP-38360 copy edits

Author: ltran-mdb2

source/snippets/reference.txt

@@ -12,6 +12,21 @@ Snippets Reference
    :depth: 1
    :class: singlecol
 
+:ref:`snip-commands`
+   An overview of the commands that are available to work with
+   :ref:`snippets <snip-overview>`.
+
+:ref:`snip-configure`
+   Options to control the interaction between ``mongosh`` and the
+   package manager that tracks individual snippet packages.
+
+:ref:`snip-errors`
+   Error handlers to specify regular expressions to catch runtime errors
+   and display custom error messages.
+
+:ref:`snip-manual-reg-index`
+   Steps to manually create a registry index file.
+
 .. toctree::
    :titlesonly: