Small improvements

plutus-core/cost-model/CostModelGeneration.md

@@ -132,9 +132,9 @@ For documentation on how to add a new built-in type, see
   the relevant builtin.  Initially this should be set to `mempty`; we'll come
   back and fix it later.
 
-  Note that there are certain restrictions on built-in functions: the
-  function should be deterministic, easy to cost, and it **must not
-  throw any exceptions.
+    Note that there are certain restrictions on built-in functions: the
+    function should be deterministic, easy to cost, and it **must not
+    throw any exceptions.
 
 3. Add a tag for the Flat encoding in `instance Flat DefaultFun` in the same
 file.  This should be different from all the existing tags and should be less