add charset UTF-8 to template exception

[uralbash]

before:

after:

[asvetlov]

I believe it's better solved by specifying correct content type for responses.
Also all rendered pages requires utf-8 perhaps.

[jettify]

hm, could we get rid from <meta charset="UTF-8" /> in templates? Specified content type should be enough

[uralbash]

@jettify Well, I removed it. If it is clear why this is necessary, you can always add

[asvetlov]

The patch is wrong, sorry.

content_type parameter is for type only, not charset.
Ctor adds ; charset=utf-8 to given parameter ultimately: https://github.com/KeepSafe/aiohttp/blob/master/aiohttp/web_reqrep.py#L742-L748

content_type='text/html' should be enough.

Perhaps we need charset param for aiohttp.web.Response ctor, I'll file the issue.

[uralbash]

@asvetlov Thanks for clarification