Property values should not be matched by \b

[weizhenye]

See following example:

@keyframes line-scale {
}
#test {
  animation: line-scale;
}

: line-scale; generates:

<span class="meta property-value css">
  <span class="punctuation separator key-value css">:</span>
  <span class="support constant property-value css">line</span>
  -scale
  <span class="punctuation terminator rule css">;</span>
</span>

For line is a constant property-value and \b regrads - as a word boundary, it goes wrong.
Same issue with constant font-name.
ES5 doesn't support lookbehind assertions, I'm not sure how to solve it.
Maybe property-values should match <ident-token> first and then constant property-value?