Improve `README.md` Noticeability.

[Jaehwa-Noh]

Make a note section easily find first in sight.

Preivew is here.

[!Note] To see the original View implementation of Sunflower, checkout the views branch.

[!Note] As Compose cannot render HTML code in Text yet. The AndroidViewBinding API is used to embed a TextView in Compose. See the PlantDescription composable in the PlantDetailView file.