Fix formatting

exercises.md

@@ -122,9 +122,8 @@
 `-r` removes PCR duplicates.\
 `-k` creates a bedgraph-ish file for pileups. \
 
-*
-    * Write the script into a Snakefile.
-        * Create a new directory `atac-seq` in your home directory for this (see the code below)
+* Write the script into a Snakefile.
+    * Create a new directory `atac-seq` in your home directory for this (see the code below)
         ```bash
         $ cd
         $ mkdir atac-seq