Fix buildifier

Author: keith

swift/internal/derived_files.bzl

@@ -295,8 +295,7 @@ def _vfsoverlay(actions, target_name):
     return actions.declare_file("{}.vfsoverlay.yaml".format(target_name))
 
 def _explicit_module_map(actions, target_name):
-    """Declares a file for the explicit module map configuration for a
-    compilation action.
+    """Declares a file for the explicit module map for a compilation action.
 
     The explicit module map file is JSON-formatted file that allows us to place
     the `.swiftmodule` files for all dependencies into a single file used for