Reference internal page directly

The external reference is no longer necessary now that the contents are
in this project.

src/conf.py

@@ -82,8 +82,6 @@
     'augur': ('https://docs.nextstrain.org/projects/augur/page/', None),
     'auspice': ('https://docs.nextstrain.org/projects/auspice/page/', None),
     'cli': ('https://docs.nextstrain.org/projects/cli/page/', None),
-    # For externally sourced snippets that reference this docs project
-    'docs.nextstrain.org': ('https://docs.nextstrain.org/page/', None),
     'nextclade': ('https://docs.nextstrain.org/projects/nextclade/page/', None),
     'ncov': ('https://docs.nextstrain.org/projects/ncov/page/', None)
 }

src/guides/bioinformatics/filtering-and-subsampling.rst

@@ -146,7 +146,7 @@ system can be used. The following examples use `Snakemake`_.
 
 2. Add two rules in a `Snakefile`_. If you are building a standard Nextstrain
    workflow, the output files should be used as input to sequence alignment. See
-   :doc:`docs.nextstrain.org:learn/parts` to learn more about the placement of
+   :doc:`../../learn/parts` to learn more about the placement of
    this step within a workflow.
 
    .. code-block:: python