ltex with html: Within source tag no html check

[Reissner]

Is your feature request related to a problem? Please describe.
In html frequently the tag source is used.
Probably most frequently as `...</script>.
The problem is, that ltex just checks within script environment as if it were text in natural language.

Describe the solution you'd like
The text within script shall either not be proved or, better, it shall be proved with the language given by the mime type.
At least for javascript this would help a lot and maybe it is not difficult to realize as ltex is already able to check standalone javascript.

Describe alternatives you've considered
Well, sometimes just linking to a separate .js file solves the problem also, but this is cumbersome for very small pieces of code.

Additional context
Should not need additional context.