Reformat public instance links in readme (#224)

Co-authored-by: Ben Busby <benbusby@protonmail.com>

README.md

@@ -339,10 +339,10 @@ A lot of the app currently piggybacks on Google's existing support for fetching
 
 *Note: Use public instances at your own discretion. Maintainers of Whoogle do not personally validate the integrity of these instances, and popular public instances are more likely to be rate-limited or blocked.*
 
-- https://whoogle.sdf.org
-- https://whoogle.tormentasolar.win/
-- https://whoogle.himiko.cloud
-- https://whoogle.kavin.rocks or http://whoogledq5f5wly5p4i2ohnvjwlihnlg4oajjum2oeddfwqdwupbuhqd.onion
+- [https://whoogle.sdf.org](https://whoogle.sdf.org)
+- [https://whoogle.tormentasolar.win/](https://whoogle.tormentasolar.win/)
+- [https://whoogle.himiko.cloud](https://whoogle.himiko.cloud)
+- [https://whoogle.kavin.rocks](https://whoogle.kavin.rocks) or [http://whoogledq5f5wly5p4i2ohnvjwlihnlg4oajjum2oeddfwqdwupbuhqd.onion](http://whoogledq5f5wly5p4i2ohnvjwlihnlg4oajjum2oeddfwqdwupbuhqd.onion)
 
 ## Screenshots
 #### Desktop