Highlight Snakemake as an implementation detail

docs/usage/cli/filter.rst

@@ -134,11 +134,12 @@ and ``--include`` to sample the data based on the intermediate strain list
 files. If the same strain appears in both files, ``augur filter`` will only
 write it once in each of the final outputs.
 
-Stitching calls together with Snakemake
-~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
+Generalizing subsampling in a workflow
+~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
 
-The approach above can be cumbersome with more intermediate samples. There is a
-more flexible approach using `Snakemake`_.
+The approach above can be cumbersome with more intermediate samples. To
+generalize this process and allow for more flexibility, a workflow management
+system can be used. The following examples use `Snakemake`_.
 
 1. Add a section in the `config file`_.