In pycodestyle 2.1.0, E305 was introduced, which requires two blank
lines after top level declarations, too.
See also #10689; thanks @stepshal for first mentioning this issue and
We need a proper lexer to be able to understand YouTube's code, which contains /* inside of strings.
For now it's sufficient to just disable comment support altogether.
Fixes #4976, fixes #4979, fixes #4980, fixes #4981, fixes #4982.
In preparation for #4822, extend jsinterp by a lot. (We may even have to/want to write a proper interpreter with actual parsing)