Improve "not found" error messages in `<sequence>.<method>()` failures

The docstring of list.remove() says value parameter as shown below:

print(help(list.remove))
# remove(self, value, /) unbound builtins.list method
#     Remove first occurrence of value.
#
#     Raises ValueError if the value is not present.

But the error message says x instead of value as shown below and I don't think list.remove(x): is necessary:

v = ['a', 'b', 'c']

v.remove('B')
# ValueError: list.remove(x): x not in list

So, the error message should just say as shown below:

ValueError: value not in list

In addition, the docstring of bytearray.remove() says valueparameter as shown below:

print(help(bytearray.remove))
# remove(self, value, /) unbound builtins.bytearray method
#     Remove the first occurrence of a value in the bytearray.
#
#     value
#       The value to remove.

And, the error message reasonably says value as shown below but I don't think found is necessary:

v = bytearray(b'abc')

v.remove(ord('B'))
# ValueError: value not found in bytearray

So, the error message should just say as shown below:

ValueError: value not in bytearray

Linked PRs

• gh-137509
• gh-139696

Start by locating the implementations and tests for list.remove() and bytearray.remove(), using the reported examples as the behavioral baseline. Check linked PRs gh-137509 and gh-139696 before starting; done means the two error messages match the requested wording and the relevant tests pass.