fix link to doc in autogenerated conf (and uses bitly)
Using an URL minifier for that will let me change the link
if I build a proper documentation site.
Fix
@@ -128,7 +128,7 @@ const DEFAULT_CONF_FILE: &str = r#"
# or one of the built-in commands.
#
# The configuration documentation and complete list of built-in verbs
-# can be found in https://github.com/Canop/broot/documentation.md
+# can be found in https://bit.ly/broot-doc
###############################
