errors: use detailed exit code in pathauditor Differential Revision: https://phab.mercurial-scm.org/D11830

errors: use detailed exit code for RepoLookupError Differential Revision: https://phab.mercurial-scm.org/D11829

errors: use detailed exit code for detected case-collision Differential Revision: https://phab.mercurial-scm.org/D11828

errors: use detailed exit code when trying to merge file outside narrowspec Differential Revision: https://phab.mercurial-scm.org/D11827

errors: use detailed exit code for non-integer number of diff context lines Differential Revision: https://phab.mercurial-scm.org/D11826

patch: add hint about mangled whitespace on bad patch One of the most common reasons that a patch doesn't apply is because its whitespace has been mangled (e.g. by their mail client or though copy&paste). Let's provide a hint about that. Differential Revision: https://phab.mercurial-scm.org/D11825

errors: return more detailed errors when failing to parse or apply patch This patch adds subclasses of `PatchError` so we can distinguish between failure to parse a patch from failure to apply it. It updates the callers to raise either `InputError` or `StateError` depending on which type of error occurred. Differential Revision: https://phab.mercurial-scm.org/D11824

extensions: add a default "*" suboptions prefix This is similar to what we do in other section (e.g. `paths`) and allow to change the behavior for all extensions. Sub options on individual extensions overwrite the default settings. Differential Revision: https://phab.mercurial-scm.org/D11823

extension: add a `required` suboption to enforce the use of an extensions If `required` is set, failing to load an extensions will abort. See the test and documentation for details. Differential Revision: https://phab.mercurial-scm.org/D11822

extensions: highlight the name of the faulty extensions in the error message This make it easier to understand the message when the extensions name is common. Differential Revision: https://phab.mercurial-scm.org/D11821