Issue 46777: Fix incorrect use of directives in asyncio documentation

There are some issues with formatting added or removed parameters in the asyncio module.

1. "deprecated-removed" directives were used for already removed directives. It should be used for deprecated features with known term of removal. For removed features "versionchanged" is more appropriate.

2. Text for removed parameters was too verbose. "Removed the XXX parameter" would be enough.

3. "versionadded" directives were used for new parameters. "versionchanged" directive is more appropriate. It is a date of the change in existing function, not the date of adding the function itself.

4. Some directives were written not in order of increasing version number.

5. In some places parameters were marked up as ``name``. *name* is commonly used for parameters.

6. The loop parameter of Task() was documented as both removed and required (if there is no current event loop) in 3.10.

New changeset 2923d87ca258b9d421e8147b12f0d98295ee3f8e by Serhiy Storchaka in branch 'main':
bpo-46777: Fix incorrect use of directives in asyncio documentation (GH-31388)
https://github.com/python/cpython/commit/2923d87ca258b9d421e8147b12f0d98295ee3f8e

New changeset 6eb34772fda2e46ba9a265e038b6e0f303bd790e by Miss Islington (bot) in branch '3.10':
bpo-46777: Fix incorrect use of directives in asyncio documentation (GH-31388)
https://github.com/python/cpython/commit/6eb34772fda2e46ba9a265e038b6e0f303bd790e

> 6. The loop parameter of Task() was documented as both removed and required (if there is no current event loop) in 3.10.

I think we should drop Task() constructor definition from Task Object docs https://docs.python.org/3/library/asyncio-task.html#task-object but create 'asyncio-extending.rst' (suggest better name please) with low-level task documentation for guys who want to create their own task class.

Task constructor could be documented here along with `_register_task()`, `_enter_task()`, `_leave_task()`, `_unregister_task()`. They might be useful for ones who implements a custom task factories.