[css-typed-om-2] Double bracket non-elements (#1019)

Author: nschonni

css-typed-om-2/Overview.bs

@@ -17,15 +17,15 @@ Issue(163): Need to add a section describing unions of types.
 
 Issue(161): Need to add a section describing shorthands.
 
-Issue(158): Spec up URIValue, ShapeValue, StringValue, CounterValue, TimeValue, PercentageValue, FrequencyValue, VoiceValue, CustomIdentValue, TransitionTimingFunctionValue. What is attr(<identifier>) in other specs?
+Issue(158): Spec up URIValue, ShapeValue, StringValue, CounterValue, TimeValue, PercentageValue, FrequencyValue, VoiceValue, CustomIdentValue, TransitionTimingFunctionValue. What is attr(<<identifier>>) in other specs?
 
 Issue(155): Do we want to make a generic PairValue and QuadValue, or have more specific classes for background-size, border-image-repeat, border-radius-*, border-image-outset, border-image-width?
 
-Issue(153): BorderImageSliceValue represents [<number> | <percentage>]{1,4} && fill?
+Issue(153): BorderImageSliceValue represents [<<number>> | <<percentage>>]{1,4} && fill?
 
-Issue(152): What do we do for play-during, which takes <uri> [ mix || repeat ]?
+Issue(152): What do we do for play-during, which takes <<uri>> [ mix || repeat ]?
 
-Issue(150): Do we want a pair type for things like quotes which take [<string> <string>]
+Issue(150): Do we want a pair type for things like quotes which take [<<string>> <<string>>]
 
 Issue(142): Do we want a font value class? How about a FontWeightValue (for 100, 200 etc) class?