Fix numbered list in docstring (#636)

Author: Ashley Scillitoe

alibi_detect/utils/missing_optional_dependency.py

@@ -20,10 +20,11 @@
 
 """Mapping used to ensure correct pip install message is generated if a missing optional dependency is detected. This
 dict is used to control two behaviours:
-    1. When we import objects from missing dependencies we check that any `ModuleNotFoundError` or `ImportError`
+
+1. When we import objects from missing dependencies we check that any `ModuleNotFoundError` or `ImportError`
     corresponds to a missing optional dependency by checking the name of the missing dependency is in `ERROR_TYPES`. We
     then map this name to the corresponding optional dependency bucket that will resolve the issue.
-    2. Some optional dependencies have multiple names such as `torch` and `pytorch`, instead of enforcing a single
+2. Some optional dependencies have multiple names such as `torch` and `pytorch`, instead of enforcing a single
     naming convention across the whole code base we instead use `ERROR_TYPES` to capture both cases. This is done right
     before the pip install message is issued as this is the most robust place to capture these differences.
 """