branching: merge with stable

style: fix various flake8 warning

next: set if we need to evolve or not; also move logic to appropriate pos set the value `needevolve` and also move the logic to find aspiringchildren to appropriate position i.e before we suggest user to use other flags like --merge.

next: move some code to prepare for `next --evolve` by default Moved some values before the block where we suggest the user to use --merge flag. As we would need these values to find if we need to evolve or not before we can suggest user to use `--merge` flag. We will suggest user to use `--merge` flag only when we don't need to evolve. Because currently we don't support both --evolve(going to be True by default) and --merge at the same time.

branching: merge with stable

topic: improve UX by using pager only when we should Before this patch we were using pager in every case of topic command, either it is setting up a new topic or clearing the active topic. After this patch it will not use pager in following commands: $ hg topic [TOPIC] -r [rev] $ hg topic --clear

evolvecmd: _possibledestination() skip visiting empty parent I see that even in the case when "parent == -1" we are visiting that also and find succsets for that and in last -1 is being added in the set of possible destination. Why not skip that?

pick: `hg help` was not showing the full cmd desc of `pick` after running command `hg help` it was not including the second line of command description. I guess it picks the firstline only. So I moved that part in first line of cmd description.

test-compat: merge mercurial-4.4 into mercurial-4.3

test-compat: merge mercurial-4.5 into mercurial-4.4