Add a directory listing feature for file URLs (#32580)

Signed-off-by: Bobulous <Bobulous@users.noreply.github.com>
Signed-off-by: Martin Robinson <mrobinson@igalia.com>
Co-authored-by: Bobulous <Bobulous@users.noreply.github.com>

components/config/prefs.rs

@@ -551,6 +551,9 @@ mod gen {
                     #[serde(rename = "network.http-cache.disabled")]
                     disabled: bool,
                 },
+                local_directory_listing: {
+                    enabled: bool,
+                },
                 mime: {
                     sniff: bool,
                 }