prune: fix small grammatical issues in help text

docs: update evolve-faq.rst with new prune flag and proper vocabulary Also strip trailing newlines.

prune: spell --successor flag without any unnecessary shortcuts If a user wants to spell out -s, it makes sense to allow that. Before this patch, prune would complain that --successor is not a recognized option. Obviously people don't usually need to spell --successors by hand thanks to shell completion (at least for Bash) using debugcomplete to see all available flags, so this patch doesn't bring any need for more typing. And thanks to Mercurial understanding shortened forms of command-line flags as long as they are unambiguous, the old-style `--succ` flags still work normally, and there are tests that use them. But two tests now use the full form to demonstrate that both ways work.

py3: redefine "troublecategories" in evolve as a dict We'll want to the keys to be bytes and the values to be unicode on py3. Having it defined as a dict makes that easier (instead of converting between the types with e.g. pycompat.sysbytes()). It was kind of ugly to convert between the forms by stripping '_' from the string anyway.

py3: store to __doc__ as str (unicode on py3)

py3: also catch ImportError when relative import fails Python 3 apparently raises an ImportError where Python 2 raised a ValueError.

py3: convert exceptions to bytes using pycompat.bytestr()

py3: use "%d" for formatting integers

py3: avoid "%s" for formatting None

py3: use "%f" for formatting floating point number

py3: fix progress() functions to not use "%s" with int Python3 doesn't support "%s" with int arguments (and not with None arguments either, which this code was also using).

py3: make random topic name generation consistent across py2/py3 random.choice() (and others based on random.randint()) changed between py2 and py3 without a way to get the py2 behavior. However, random.random() did not change, so we can re-implement random.choice() based on that.

py3: convert str to bytes before passing to core exception

py3: convert opts keys to bytes before passing to core APIs

evolve: further clarify when update is performed

py3: avoid comparing int and None

py3: avoid "%r" for list of byte strings, which produces b'' on py3

py3: avoid "%r" for byte string, which produces b'' on py3 Replaced by "'%s'", which I think is clearer anyway.

py3: replace str(ctx) by bytes(ctx) These are all for messages to the user and we don't want unicode for that.

py3: use inspect.signature() instead of inspect.getargspec() on py3

py3: use array.array.{to,from}bytes() on py3 array.array.{to,from}string() still exists on py3, but they're deprecated and generate warnings. I've put the compat function in compat.pt for now. We can move into a dedicated pycompat.py if we end up with a lot of py3 compat stuff.

py3: config values can be bytes, but never unicode

py3: call branchmap.items() on py3 and continue to call iteritems() on py2 Mercurial's source transformer also replaces the 'def iteritems(' in branchmap by 'def items(', so we need to call whichever version is there.

py3: switch from iteritems() to items() in the topics extension The only remaining iteritems() call is on branchmap. That will be dealt with in the next patch.

py3: filter() now returns a generator, so wrap when we need a list

py3: don't depend on map() iterating over its input map(some_generator()) in py2 returns a list, while in py3 it returns a generator, so the passed-in generator won't be called unless the returned one is.

py3: implement __bool__ in addition to __nonzero__

py3: replace iter.next() by next(iter)