Fix Python: broken format string in API docs

This example was currently broken:
https://docs.blender.org/api/current/bpy.props.html#operator-example

Pull Request: https://projects.blender.org/blender/blender/pulls/136937

doc/python_api/examples/bpy.props.1.py

@@ -7,6 +7,7 @@ classes. Test this code by running it in the text editor, or by clicking the
 button in the 3D View-port's Tools panel. The latter will show the properties
 in the Redo panel and allow you to change them.
 """
+
 import bpy
 
 
@@ -21,7 +22,7 @@ class OBJECT_OT_property_example(bpy.types.Operator):
 
     def execute(self, context):
         self.report(
-            {'INFO'}, "F: {:.2f}  B: {:s}  S: {!r}".format(
+            {'INFO'}, "F: {:.2f}  B: {!s}  S: {!r}".format(
                 self.my_float, self.my_bool, self.my_string,
             )
         )