efg_writer -> efg_writer.cc

Author: rahulsavani

content/gsoc_2026.md

@@ -321,7 +321,7 @@ and also better documented.
 Here are pointers to the existing exporters (two for each type of game format):
 
 - [EFG exporter in python](https://github.com/google-deepmind/open_spiel/blob/master/open_spiel/python/algorithms/gambit.py)
-- [Independent EFG exporter in C++](https://github.com/google-deepmind/open_spiel/blob/master/open_spiel/game_transforms/efg_writer)
+- [Independent EFG exporter in C++](https://github.com/google-deepmind/open_spiel/blob/master/open_spiel/game_transforms/efg_writer.cc)
 - [NFG exporter written in C++](https://github.com/google-deepmind/open_spiel/blob/master/open_spiel/algorithms/nfg_writer.cc), 
     exposed to Python and [tested](https://github.com/google-deepmind/open_spiel/blob/master/open_spiel/python/tests/nfg_writer_test.py)