py3: implement __bool__ in addition to __nonzero__

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

py3: replace xrange() by range()

py3: read sqlite3 data as bytes The py2 and py3 docs ([1] and [2]) disagree how to get bytes output, but it seems obvious that this should be "bytes" to be compatible with both. [1] https://docs.python.org/2/library/sqlite3.html#sqlite3.Connection.text_factory [2] https://docs.python.org/3/library/sqlite3.html#sqlite3.Connection.text_factory

py3: sqlite3.connect() expects str arguments

cleanup: remove check only needed for hg versions before 4.4 ui.edit() has had the "action" argument since 6e6452bc441d (editor: use an unambiguous path suffix for editor files, 2017-08-30), which was first released in hg version 4.4. Since we support only versions higher than 4.5, we can drop this check.

split: remove an unnecessary (and confusingly typed) fallback revision `opts.get('rev') or '.'` is either a list of strings or just a string. It happened to work because `'.'[0] == '.'` on Python 2, but it won't work on Python 3 (for byte strings). The fallback value wasn't even needed (it was also set just after), so let's just remove it.

evolve: rename variable "children" to "child" where it's clearly singular

evolve: remove some unused variables

py3: back out 23323092f0a7 D6623 has now been accepted in Mercurial (commit 83666f011679), so evolve commit 23323092f0a7 (py3: convert _origdoc to sysstr to match __doc__, 2019-07-09) is not longer needed.