Fix --git deducing ignored state in unintuitive way

It makes sense to consider that a directory has the aggregated status of all the files under it.

The exception is that for the ignored status, it’s more useful and intuitive to consider that it applies to everything under it.

- A directory containing an ignored file is no longer considered ignored
- A file inside an ignored directory is now considered ignored

src/fs/feature/git.rs

@@ -252,15 +252,21 @@ impl Git {
             .unwrap_or_default()
     }
 
-    /// Get the combined status for all the files whose paths begin with the
-    /// path that gets passed in. This is used for getting the status of
-    /// directories, which don’t really have an ‘official’ status.
+    /// Get the combined, user-facing status of a file or directory.
+    /// Statuses are aggregating (for example, a directory is considered
+    /// modified if any file under it has the status modified), except
+    /// for ignored which applies to files under (for example, a file is
+    /// considered ignored if one of its parent directories is ignored)
     fn dir_status(&self, dir: &Path) -> f::Git {
         let path = reorient(dir);
 
         let s = self.statuses.iter()
-                    .filter(|p| p.0.starts_with(&path))
-                    .fold(git2::Status::empty(), |a, b| a | b.1);
+            .filter(|p| if p.1 == git2::Status::IGNORED {
+                path.starts_with(&p.0)
+            } else {
+                p.0.starts_with(&path)
+            })
+            .fold(git2::Status::empty(), |a, b| a | b.1);
 
         let staged = index_status(s);
         let unstaged = working_tree_status(s);