don't read 'the twenty fifth of december' as a fraction - #1257

The [#Card+ #Ord] of . fraction rule also caught spelled-out compound ordinals:

nlp('the twenty fifth of december').numbers().get()  // [4]   (20/5)
nlp('the twenty-third of june').numbers().get()      // [6.667]
// with compromise-dates, 'the twenty fifth of december' is december 4th

A fraction with a numerator above one has a plural ordinal ('two thirds of'), and 'one third of' / 'a twenty fifth of' are already covered by the (a|one) rule, so this rule now only takes a plural ordinal. 'two thirds of', 'three fifths of' and 'nine tenths of' are unchanged. Tests added to fractions.test.js and to the dates plugin's explicit-dates test; they fail on dev and pass with the change. The full suite and the plugin suites pass.

I used Claude Code to write this change.