docs(assets): add note to inlining SVG through url() (vitejs#15534)

Co-authored-by: 翠 / green <[email protected]>

docs/guide/assets.md

@@ -30,6 +30,16 @@ The behavior is similar to webpack's `file-loader`. The difference is that the i
 
 - TypeScript, by default, does not recognize static asset imports as valid modules. To fix this, include [`vite/client`](./features#client-types).
 
+::: tip Inlining SVGs through `url()`
+When passing a URL of SVG to a manually constructed `url()` by JS, the variable should be wrapped within double quotes.
+
+```js
+import imgUrl from './img.svg'
+document.getElementById('hero-img').style.background = `url("${imgUrl}")`
+```
+
+:::
+
 ### Explicit URL Imports
 
 Assets that are not included in the internal list or in `assetsInclude`, can be explicitly imported as a URL using the `?url` suffix. This is useful, for example, to import [Houdini Paint Worklets](https://houdini.how/usage).