[issue29051] Improve error reporting involving f-strings (PEP 498)

[Serhiy Storchaka]

Changes by Serhiy Storchaka <storchaka+cpython at gmail.com>:


----------
dependencies: +Tracebacks should contain the first line of continuation lines

_______________________________________
Python tracker <report at bugs.python.org>
<http://bugs.python.org/issue29051>
_______________________________________