[docs] improve the writing on the "Quick filter outside of the grid" example

[michelengelen]

• [x] I have followed (at least) the PR section of the contributing guide.

---

noticed that the sentence structure was a bit off. Took the chance to improve the wording on the section a bit

[mui-bot]

Deploy preview: https://deploy-preview-13155--material-ui-x.netlify.app/

Updated pages:

• docs/data/data-grid/filtering-recipes/filtering-recipes.md

Generated by :no_entry_sign: dangerJS against 958ba06a92f772e014e831ed5d4c6306055f000e