tests/test-wireproto.py.out

templater: allow piping generator-type function output to filters

Template functions use "yield"s assuming that the result will be combined
into a string, which means both "f -> str" and "f -> generator" should behave
in the same way.

Before this patch, piping generator function resulted in a cryptic error.
We had to insert "|stringify" in this case.

  $ hg log --template '{if(author, author)|user}\n'
  abort: template filter 'userfilter' is not compatible with keyword
  '[(<function runsymbol at 0x7f5af2e8d8c0>, 'author'),
    (<function runsymbol at 0x7f5af2e8d8c0>, 'author')]'

Hello, Foobar
['Hello, Fo, =;o', 'Hello, Bar']