[css-scoping] Add manual ID to >>> definition.

--HG--
extra : rebase_source : 0bdf9e1962b638c661e4ae07223647dac1e270c3
[selectors] Add anchors to combinators.

--HG--
extra : rebase_source : 1fbc4aaaeb2bd18312dff797adac5ac00706757b
[css-align] Rename <item-position> to <self-position>, so both productions reference the properties they're used in.

--HG--
extra : rebase_source : 71475b0447b0f139349cfbb8d59d50a7f7249d63