[idea] toggleAttribute along with a particular value

For example,

// Assume we start with `el` already having the `foo` attribute:
el.toggleAttribute('foo', 'bar') // no longer has attribute `foo`
el.toggleAttribute('foo', 'bar') // now has attribute `foo` with value `bar`
el.toggleAttribute('foo', 'bar') // no longer has attribute `foo`
el.toggleAttribute('foo', 'bar') // now has attribute `foo` with value `bar`

• If the attribute exists, remove it. This is similar to calling removeAttribute('foo') while the attribute exists.
• If the attribute does not exist, add it, with the given value. This is similar to calling setAttribute('foo', 'bar') while the attribute does not exist.

The above code would be equivalent to this:

// Assume we start with `el` already having the `foo` attribute:
el.removeAttribute('foo') // no longer has attribute `foo`
el.setAttribute('foo', 'bar') // now has attribute `foo` with value `bar`
el.removeAttribute('foo') // no longer has attribute `foo`
el.setAttribute('foo', 'bar') // now has attribute `foo` with value `bar`