Add __repr__ method to File class (#2550)

mkdocs/structure/files.py

@@ -141,6 +141,11 @@ class File:
     def __ne__(self, other):
         return not self.__eq__(other)
 
+    def __repr__(self):
+        return "File(src_path='{}', dest_path='{}', name='{}', url='{}')".format(
+            self.src_path, self.dest_path, self.name, self.url
+        )
+
     def _get_stem(self):
         """ Return the name of the file without it's extension. """
         filename = os.path.basename(self.src_path)