docs: start description of commit message with lowercase letter (#2938)

Co-authored-by: Jo Franchetti <jofranchetti@gmail.com>

Author: NikitaKorevo

runtime/contributing/index.md

@@ -101,9 +101,9 @@ done:
 
 Examples of good PR title:
 
-- fix(std/http): Fix race condition in server
-- docs(console): Update docstrings
-- feat(doc): Handle nested re-exports
+- fix(std/http): fix race condition in server
+- docs(console): update docstrings
+- feat(doc): handle nested re-exports
 
 Examples of bad PR title: