Enhancement: Select the minimum length format for strings

[mcandre]

To further shrink SVG content, we can select string literal formats tailored to reduce the number of escape characters involved, for each individual string constant. E.g., '"' is preferable to "\"", and "'" is preferable to '\''.

• For each string constant, compare how the constant would be quote-escaped in double- vs. single-quoted formatted literals.
• Select the minimal length format for that particular string constant and emit to output.

[SethFalco]

This is interesting, I'm assuming this mostly applies to attribute values. Overall, it looks like we don't need to encode quot/apos entities if they're used in the other kind of quote.

On MDN, we can see various SVGs use different kinds of quotes for attribute values.

See: https://developer.mozilla.org/en-US/docs/Web/SVG/Element/svg

On W3's SVG 1.1 validator, the following SVG passes, no need to encode XML entities:

<!DOCTYPE svg PUBLIC "-//W3C//DTD SVG 1.1//EN" "http://www.w3.org/Graphics/SVG/1.1/DTD/svg11.dtd">
<svg xmlns="http://www.w3.org/2000/svg" xmlns:xlink="http://www.w3.org/1999/xlink" >
<title>uwu</title>
<a xlink:href="uwu'owo"/>
<a xlink:href='uwu"owo'/>
</svg>

See: https://validator.w3.org/check

Assuming there are no consequences of this, we could achieve this by updating the types of of attrStart and attrEnd to be string | ((value: string) => string) and use one based on what would be smaller. This also preserved backward compatibility.