improve docs related to authentication when fetching

Author: Byron

git-repository/src/remote/connection/access.rs

@@ -12,6 +12,10 @@ impl<'a, 'repo, T, P> Connection<'a, 'repo, T, P> {
     /// user.
     ///
     /// A custom function may also be used to prevent accessing resources with authentication.
+    ///
+    /// Use the [configured_credentials()][Connection::configured_credentials()] method to obtain the implementation
+    /// that would otherwise be used, which can be useful to proxy the default configuration and obtain information about the
+    /// URLs to authenticate with.
     pub fn with_credentials(
         mut self,
         helper: impl FnMut(git_credentials::helper::Action) -> git_credentials::protocol::Result + 'a,