[Fonts] Update WOFF2 percentage from 82% to 65%

The featured stat claims that 82% of font requests were served using WOFF2, but the [chapter text](https://almanac.httparchive.org/en/2025/fonts#file-formats-and-optimization) doesn't support that. It mentions 65% instead.

Author: christianliebel

src/content/en/2025/fonts.md

@@ -15,7 +15,7 @@ featured_stat_1: 72%
 featured_stat_label_1: websites self-hosting fonts in some capacity
 featured_stat_2: 40%
 featured_stat_label_2: websites using variable fonts
-featured_stat_3: 82%
+featured_stat_3: 65%
 featured_stat_label_3: font requests served as WOFF2
 doi: 10.5281/zenodo.18246295
 ---