transformers

0b933584 - Fix usage of head masks by TF encoder-decoder models' `generate()` function (#11775)

Fix usage of head masks by TF encoder-decoder models' `generate()` function (#11775) * Fix Bart * Fix Blenderbot{,_small} * Fix LED * Fix Marian * Fix MBart * Fix Pegasus * Fix T5 * Add test for generation with head_mask * Add a common TF test * Override a test for the LED model as head masking is not yet properly implemented * Remove all head_masks from input preparation for LED * Drop masking for T5 as it needs a bit of refactor