[Docs] Fix spelling and grammar mistakes (#28825)

* Fix typos and grammar mistakes in docs and examples

* Fix typos in docstrings and comments

* Fix spelling of `tokenizer` in model tests

* Remove erroneous spaces in decorators

* Remove extra spaces in Markdown link texts

docs/source/en/testing.md

@@ -976,7 +976,7 @@ Some decorators like `@parameterized` rewrite test names, therefore `@slow` and
 `@require_*` have to be listed last for them to work correctly. Here is an example of the correct usage:
 
 ```python no-style
-@parameteriz ed.expand(...)
+@parameterized.expand(...)
 @slow
 def test_integration_foo():
 ```