HH-47330 add fail_on_error kwarg to MicroHandler HTTP client methods
HH-47330 add xsl syntax error test
HH-47330 update docs
HH-47330 fix tests with lxml >= 3
HH-47330 use tornado.autoreload.watch alias
HH-47330 set AsyncGroup default level to INFO
Merge remote-tracking branch 'origin/HH-47330' into EXP-12842
release 2.21.19 [an.sumin@hh.ru]