develwarn: include call site in the simple message version
Just displaying the warning makes it quite hard to recognise the guilty code
quickly and using --traceback for all calls is not very convenient. So we
include the call site with all simple message to help developer to recognise
errors sources.
$ hg init
$ echo This is file a1 > a
$ hg add a
$ hg commit -m "commit #0"
$ ls
a
$ echo This is file b1 > b
$ hg add b
$ hg commit -m "commit #1"
$ hg co 0
0 files updated, 0 files merged, 1 files removed, 0 files unresolved
B should disappear
$ ls
a