Part of #9744
Removes all redundant `# -*- coding: utf-8 -*-` lines from files, as python 3 automatically reads source code as utf-8 now.
`Signed-off-by: Jonathan de Jong <jonathan@automatia.nl>`
The general idea here is that config examples should just have a hash and no
extraneous whitespace, both to make it easier for people who don't understand
yaml, and to make the examples stand out from the comments.
Server Notices use a special room which the user can't dismiss. They are
created on demand when some other bit of the code calls send_notice.
(This doesn't actually do much yet becuse we don't call send_notice anywhere)
