split seq2seq script into summarization & translation (#10611)

* split seq2seq script, update docs

* needless diff

* fix readme

* remove test diff

* s/summarization/translation

Co-authored-by: Sylvain Gugger <35901082+sgugger@users.noreply.github.com>

* cr

* fix arguments & better mbart/t5 refs

* copyright

Co-authored-by: Suraj Patil <surajp815@gmail.com>

* reword readme

Co-authored-by: Suraj Patil <surajp815@gmail.com>

* s/summarization/translation

* short script names

* fix tests

* fix isort, include mbart doc

* delete old script, update tests

* automate source prefix

* automate source prefix for translation

* s/translation/trans

Co-authored-by: Stas Bekman <stas00@users.noreply.github.com>

* fix script name (short version)

* typos

Co-authored-by: Stas Bekman <stas00@users.noreply.github.com>

* exact parameter

Co-authored-by: Stas Bekman <stas00@users.noreply.github.com>

* remove superfluous source_prefix calls in docs

* rename scripts & warn for source prefix

* black

* flake8

Co-authored-by: theo <theo@matussie.re>
Co-authored-by: Sylvain Gugger <35901082+sgugger@users.noreply.github.com>
Co-authored-by: Suraj Patil <surajp815@gmail.com>
Co-authored-by: Stas Bekman <stas00@users.noreply.github.com>

examples/tests/deepspeed/test_deepspeed.py

@@ -233,7 +233,6 @@ class TestDeepSpeed(TestCasePlus):
             --group_by_length
             --label_smoothing_factor 0.1
             --adafactor
-            --task translation
             --target_lang ro_RO
             --source_lang en_XX
         """.split()
@@ -246,7 +245,7 @@ class TestDeepSpeed(TestCasePlus):
             args = [x for x in args if x not in remove_args]
 
         ds_args = f"--deepspeed {self.test_file_dir_str}/ds_config.json".split()
-        script = [f"{self.examples_dir_str}/seq2seq/run_seq2seq.py"]
+        script = [f"{self.examples_dir_str}/seq2seq/run_translation.py"]
         num_gpus = get_gpu_count() if distributed else 1
         launcher = f"deepspeed --num_gpus {num_gpus}".split()