[dualfroz]

Problem

A bounded PDeque (created with maxlen) loses its bound when passed through
remove() or reverse():

from pyrsistent import pdeque
d = pdeque([1, 2, 3], maxlen=3)
d.remove(2).maxlen     # None  -- expected 3
d.reverse().maxlen     # None  -- expected 3

Because the bound is silently dropped, the result no longer enforces its
maximum length, so subsequent appends can grow it past the declared maxlen:

pdeque([1, 2, 3], maxlen=3).remove(2).append(4).append(5)
# pdeque([1, 3, 4, 5])   -- 4 elements in a maxlen=3 deque

Root cause

pyrsistent/_pdeque.py. PDeque.__new__ accepts maxlen=None as a default.
Every structural method threads self._maxlen into the new instance
(pop, popleft, append, extend, ...), except two:

• remove() built its results with PDeque(..., self._length - 1), omitting
  the maxlen argument (both the left-list and the right-list branches).
• reverse() built its result with PDeque(self._right_list, self._left_list, self._length), omitting maxlen.

Both therefore defaulted maxlen to None.

Fix

Pass self._maxlen through in both methods, matching every other structural
operation on PDeque.

Test

tests/deque_test.py::test_remove_preserves_maxlen and
::test_reverse_preserves_maxlen assert the returned deque keeps maxlen == 3
and stays bounded across a following append. (PDeque.__eq__ compares only the
elements and ignores maxlen, so the tests check .maxlen directly.)

Both fail on the current master (assert None == 3) and pass with the fix.