[spec] fix comparison to grammar productions

See #60

spec.emu

@@ -54,11 +54,11 @@ contributors: Jordan Harband
           1. Let _toEscape_ be a CharSet containing every character in the ASCII punctuators that need escaping.
           1. Let _escapedList_ be a new empty List.
           1. For each code point _c_ in _cpList_, do
-            1. If _escapedList_ is empty and _c_ is a |DecimalDigit|, then
+            1. If _escapedList_ is empty and _c_ is matched by |DecimalDigit|, then
               1. Append code unit U+005C (REVERSE SOLIDUS) to _escapedList_.
               1. Append code unit U+0078 (LATIN SMALL LETTER X) to _escapedList_.
               1. Append code unit U+0033 (DIGIT THREE) to _escapedList_.
-            1. Else if _c_ is a CharSetElement of _toEscape_ or is |WhiteSpace|, then
+            1. Else if _c_ is a CharSetElement of _toEscape_ or is matched by |WhiteSpace|, then
               1. Append code unit U+005C (REVERSE SOLIDUS) to _escapedList_.
             1. Append the elements of UTF16EncodeCodePoint(_c_) to _escapedList_.
           1. Return CodePointsToString(_escapedList_).