credits: Simplify Threadbare GitHub URL

Author: wjt

scenes/menus/title/components/credits.tscn

@@ -419,7 +419,7 @@ size_flags_vertical = 3
 bbcode_enabled = true
 text = "Threadbare is open-source. Join our community, make a contribution, and add your name to these credits!
 
-[url]https://github.com/endlessm/threadbare/[/url]"
+[url=https://github.com/endlessm/threadbare/]github.com/endlessm/threadbare[/url]"
 fit_content = true
 horizontal_alignment = 1