[css-text] issues-lc-2013 incorporated responses from I18N WG

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extra : rebase_source : 9bfb1554376ca18320e609ddf92c48a12c338832
[css-syntax] Need to check for EOF when testing to see if it's a valid escape.

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extra : rebase_source : 9ce605f0100222ba60f4c09d9b1b742c8f548268
[css-syntax] Revert that last change.