bookmarks: drop deprecated methods (API)
The ProgrammingError prevents accidental usage of the dict base class methods.
.. api::
The following deprecated methods have been removed from bookmarks:
__setitem__(), __delitem__(), update(), and recordchange(). Use
bookmarks.applychanges() instead.
#
# Avoid interference from actual test env:
unset HGTEST_JOBS
unset HGTEST_TIMEOUT
unset HGTEST_PORT
unset HGTEST_SHELL