ui: add a "config_default" method
This allow code to access the expected value for a config. This is useful in the
context of dynamic default value, and short term it will be useful to write
dynamically "correct" code.
Differential Revision: https://phab.mercurial-scm.org/D9759
Mercurial evolves over time, some features, options, commands may be replaced by
better and more secure alternatives. This topic will help you migrating your
existing usage and/or configuration to newer features.
Commands
========
The following commands are still available but their use are not recommended:
``locate``
This command has been replaced by `hg files`.
``parents``
This command can be replaced by `hg summary` or `hg log` with appropriate
revsets. See `hg help revsets` for more information.
``tip``
The recommended alternative is `hg heads`.
Options
=======
``web.allowpull``
Renamed to `allow-pull`.
``web.allow_push``
Renamed to `allow-push`.