Merge pull request w3c#379 from w3c/issue-378

[css-masking-1] Add missing managed longhand prop to mask-border. w3c#378

Author: dirkschulze

css-masking-1/Overview.bs

@@ -1096,9 +1096,9 @@ Media: visual
 Animation type: See individual properties
 </pre>
 
-This is a shorthand property for setting 'mask-border-source', 'mask-border-slice', 'mask-border-width', 'mask-border-outset' and 'mask-border-repeat'. Omitted values are set to their initial values.
+This is a shorthand property for setting 'mask-border-source', 'mask-border-slice', 'mask-border-width', 'mask-border-outset', 'mask-border-repeat' and 'mask-border-mode'. Omitted values are set to their initial values.
 
-Note: The 'mask' shorthand resets the properties 'mask-border', 'mask-border-source', 'mask-border-mode', 'mask-border-slice', 'mask-border-width', 'mask-border-outset' and 'mask-border-repeat'.
+Note: The 'mask' shorthand resets the properties 'mask-border', 'mask-border-source', 'mask-border-slice', 'mask-border-width', 'mask-border-outset', 'mask-border-repeat' and 'mask-border-mode'.
 
 
 ## Masking with the mask border image ## {#masking-with-the-mask-border-image}