update bulleted list formatting in assert_produces_warning

Author: dave-lewis-alida

pandas/util/testing.py

@@ -2354,14 +2354,16 @@ class for all warnings. To check that no warning is returned,
         Specifies whether warnings are ignored, displayed, or turned
         into errors.
         Valid values are:
+
         * "error" - turns matching warnings into exeptions
         * "ignore" - discard the warning
         * "always" - always emit a warning
         * "default" - print the warning the first time it is generated
-        from each location
+          from each location
         * "module" - print the warning the first time it is generated
-        from each module
+          from each module
         * "once" - print the warning the first time it is generated
+
     clear : str, default None
         If not ``None`` then remove any previously raised warnings from
         the ``__warningsregistry__`` to ensure that no warning messages are