BiliBili - cannot parse <h1> title when it has `<` or `>` characters inside

[XVilka]

• I've verified and I assure that I'm running youtube-dl 2018.01.21
• At least skimmed through the README, most notably the FAQ and BUGS sections
• Searched the bugtracker for similar issues including closed ones

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• Bug report (encountered problems with youtube-dl)
• Site support request (request for adding support for a new site)
• Feature request (request for a new functionality)
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In line

 title = self._html_search_regex('<h1[^>]*>([^<]+)</h1>', webpage, 'title')

of https://github.com/rg3/youtube-dl/blob/master/youtube_dl/extractor/bilibili.py you do the regex search. But it is common for videos to contain > and < characters as a part of a title.

[dstftw]

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