Parse .//a//b/-prefixed paths more leniently in the file finder (#31459)

Closes https://github.com/zed-industries/zed/issues/15081
Closes https://github.com/zed-industries/zed/issues/31064

Release Notes:

- Parse `./`/`a/`/`b/`-prefixed paths more leniently in the file finder

crates/file_finder/src/file_finder_tests.rs

@@ -206,6 +206,11 @@ async fn test_matching_paths(cx: &mut TestAppContext) {
 
     for bandana_query in [
         "bandana",
+        "./bandana",
+        ".\\bandana",
+        util::separator!("a/bandana"),
+        "b/bandana",
+        "b\\bandana",
         " bandana",
         "bandana ",
         " bandana ",
@@ -224,7 +229,8 @@ async fn test_matching_paths(cx: &mut TestAppContext) {
             assert_eq!(
                 picker.delegate.matches.len(),
                 1,
-                "Wrong number of matches for bandana query '{bandana_query}'"
+                "Wrong number of matches for bandana query '{bandana_query}'. Matches: {:?}",
+                picker.delegate.matches
             );
         });
         cx.dispatch_action(SelectNext);