profiling: replace '+' markup of nested lines with indentation
The display of nested lines for hg --profile was very non-obvious and made it
look like sort didn't work.
The '+' immediately before CallCount was not related to the CallCount and did
not mean plus in any integer sense.
The '+' before module looked like a part of the module name and not like ascii
art.
Instead we now indent the subordinate module names to clearly show the
structure.
$ hg init t
$ cd t
$ echo a > a
$ hg add a
$ hg commit -m test
$ rm .hg/requires
$ hg tip
abort: index 00changelog.i unknown format 2!
[255]
$ echo indoor-pool > .hg/requires
$ hg tip
abort: unknown repository format: requires features 'indoor-pool' (upgrade Mercurial)!
[255]
$ echo outdoor-pool >> .hg/requires
$ hg tip
abort: unknown repository format: requires features 'indoor-pool', 'outdoor-pool' (upgrade Mercurial)!
[255]
$ cd ..