The HTML::Fraction encodes fractions as HTML entities. Some very
common fractions have HTML entities (eg `1/2` is `½`;). Additionally,
common vulgar fractions have Unicode characters (eg `1/5` is `⅕`). This
module takes a string and encodes fractions as entities: this means that
it will look pretty in the browser.
Fractions that are supported:

`
`

`
1/4, 1/2, 3/4, 0/3, 1/3, 2/3, 1/5, 2/5, 3/5,
4/5, 1/6, 5/6, 1/7, 1/8, 3/8, 5/8, 7/8, 1/9, 1/10
`

Fractions may be in the string in the form numerator slash denominator (`1/5`)
or in decimal form (`0.5`). Numbers must be equal to the fraction to two
decimal places. This module supports converting whole and fractional decimal
numbers (e.g. `2.25`.)

For sanity the decimal `0` will not be turned into the unicode for `0/3`

We don’t perform normalisation of the denominator and numerator so 4/6 is
not converted like `2/3` is. This is intentional.
`2.25` doesn’t render to the same thing as `2 1/2` (the latter has a space
between the digit 2 and the fraction.)

`1/7` doesn’t represent as a reoccuring pattern of digits in decimal therefore
we don’t check that digits after `0.14285714` are correct, and assume that
they are.