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
$ touch unknown
$ touch a
$ hg add a
$ hg ci -m "1"
$ touch b
$ hg add b
$ hg ci -m "2"
Should show unknown
$ hg status
? unknown
$ hg revert -r 0 --all
removing b
Should show unknown and b removed
$ hg status
R b
? unknown
Should show a and unknown
$ ls
a
unknown