Fix Black lint

Author: drpatelh

bin/multiqc_mappings_config.py

@@ -10,4 +10,4 @@
     rename = []
     for line in fin:
         rename.append(f"  - [{', '.join(line.strip().split(','))}]")
-    fout.write(config + '\n'.join(sorted(rename)) + '\n')
+    fout.write(config + "\n".join(sorted(rename)) + "\n")