gh-97959: [pydoc] now help() does not show extra notes for classmethods

[sobolevn]

Demo:

>>> class A:
...    @classmethod
...    def some(cls):
...       pass
... 
>>> help(A)

Before:

Help on class A in module __main__:

class A(builtins.object)
 |  Class methods defined here:
 |
 |  some() from builtins.type
 |
 |  ----------------------------------------------------------------------
 |  Data descriptors defined here:
 |
 |  __dict__
 |      dictionary for instance variables (if defined)
 |
 |  __weakref__
 |      list of weak references to the object (if defined)

After:

Help on class A in module __main__:

class A(builtins.object)
 |  Class methods defined here:
 |
 |  some()
 |
 |  ----------------------------------------------------------------------
 |  Data descriptors defined here:
 |
 |  __dict__
 |      dictionary for instance variables (if defined)
 |
 |  __weakref__
 |      list of weak references to the object (if defined)

Note that other use-cases for from note are still supported, I've added MethodType test case especially for that.

• Issue: pydoc renders from builtins.type note, even if it is incorrect #97959

[sobolevn]

I am not sure about the enum case:

   |  Methods inherited from enum.EnumType:
   |
-  |  __contains__(value)
+  |  __contains__(value) from enum.EnumType
   |      Return True if `value` is in `cls`.

This needs some more work.