docs: fix extension typo

See codeigniter4#5800

user_guide_src/source/libraries/publisher.rst

@@ -83,7 +83,7 @@ receive files with the following extensions:
 
 * Web assets: css, scss, js, map
 * Non-executable web files: htm, html, xml, json, webmanifest
-* Fonts: tff, eot, woff, woff2
+* Fonts: ttf, eot, woff, woff2
 * Images: gif, jpg, jpeg, tif, tiff, png, webp, bmp, ico, svg
 
 If you need to add or adjust the security for your project then alter the ``$restrictions`` property of ``Config\Publisher`` in **app/Config/Publisher.php**.