message: Update for Swift SourceManager API change
diff: @@ -2636,7 +2636,7 @@ public:
  if (source_loc.isValid()) {
  bufferID = source_mgr.findBufferContainingLoc(source_loc);
  - bufferName = source_mgr.getBufferIdentifierForLoc(source_loc);
  + bufferName = source_mgr.getDisplayNameForLoc(source_loc);
  line_col = source_mgr.getLineAndColumn(source_loc);
  }
  