fix

Author: lucasfang

docs/source/building.rst

@@ -225,11 +225,11 @@ Override only a single dependency (fmt):
 
 .. note::
 
-- The exact fetch behaviour (how the mirror prefix is concatenated, or
+  - The exact fetch behaviour (how the mirror prefix is concatenated, or
   whether the helper expects a full URL vs. a prefix) is implemented in
   ``cmake_modules/ThirdpartyToolchain.cmake``. Consult that file when you
   need a custom setup.
-- Unset an environment variable to revert to the default upstream download
+  - Unset an environment variable to revert to the default upstream download
   locations, for example:
 
 .. code-block:: shell