[WebIDL] 各種更新（ Replace serializers by toJSON and [Default] extended a…

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Add bug template URL for Chromium (
whatwg/webidl#374 )
whatwg/webidl@4269cc0
40ac0890

Add frozen array types to the list of JSON types
whatwg/webidl@375b588
27d62c6c

Editorial: minor language fix
whatwg/webidl@d42f606
a840517b

Editorial: fix toJSON algorithm example
whatwg/webidl@b323f1a
e62d9718

Replace serializers by toJSON and [Default] extended attribute (
whatwg/webidl#323 )
whatwg/webidl@a505f33
7f0877b1