Docs (Svelte): duplicate element id

[jkmik244752]

The "Spring" chapter appears twice under https://svelte.dev/docs/svelte/svelte-motion; it is impossible to hotlink the second chapter. It also breaks active chapter highlight in the aside nav.

This issue can be resolved upstream by introducing more consistent type interface naming. If the result of a Tween wrapper is a Tweened value, then the result of a Spring wrapper could be a Sprung value.