feat: add reload_file command

src/buffer/Buffer.zig

@@ -1257,6 +1257,11 @@ pub fn reset_to_last_saved(self: *Self) void {
     }
 }
 
+pub fn refresh_from_file(self: *Self) LoadFromFileError!void {
+    try self.load_from_file_and_update(self.file_path);
+    self.update_last_used_time();
+}
+
 pub fn store_to_string(self: *const Self, allocator: Allocator, eol_mode: EolMode) ![]u8 {
     var s = try ArrayList(u8).initCapacity(allocator, self.root.weights_sum().len);
     try self.root.store(s.writer(), eol_mode);