DOC: fix path to source code

Author: mj-will

docs/conf.py

@@ -15,7 +15,7 @@
 
 import nessai
 
-sys.path.insert(0, os.path.abspath("../nessai/"))
+sys.path.insert(0, os.path.abspath("../src/nessai/"))
 
 # -- Project information -----------------------------------------------------