Generate: add min_p sampling (#30639)

* min_p

* more relaxed test to avoid numerical issues

* Update src/transformers/generation/logits_process.py

Co-authored-by: menhguin <minh1228@gmail.com>

* Update src/transformers/generation/configuration_utils.py

Co-authored-by: menhguin <minh1228@gmail.com>

* docstring clarifications

* PR comments

* Update tests/generation/test_logits_process.py

Co-authored-by: amyeroberts <22614925+amyeroberts@users.noreply.github.com>

* make fixup

---------

Co-authored-by: menhguin <minh1228@gmail.com>
Co-authored-by: amyeroberts <22614925+amyeroberts@users.noreply.github.com>

docs/source/en/internal/generation_utils.md

@@ -167,6 +167,9 @@ generation.
 [[autodoc]] MinNewTokensLengthLogitsProcessor
     - __call__
 
+[[autodoc]] MinPLogitsWarper
+    - __call__
+
 [[autodoc]] NoBadWordsLogitsProcessor
     - __call__