fix more formats

Author: tbrowder

doc/Type/DateTime.pod6

@@ -262,8 +262,8 @@ Returns the instant's time as a fraction of a 24-hour day.
 
     say DateTime.new('2021-12-24T12:23:00.43Z').day-fraction; # OUTPUT: «0.5159772␤»
 
-Notice the `day-fraction` value is the same as the fractional part of
-the `modified-julian-date` for the same instant.
+Notice the C<day-fraction> value is the same as the fractional part of
+the C<modified-julian-date> for the same instant.
 
 =head2 method julian-date