Automatic selection of language based on query parameters

[Andre601]

This can be seen as an addition to #9

My suggestion is, to allow the language to be (pre-)selected based on a query parameter defined in the URL.
This would allow people to share a link, where the code highlighting is already set, only requiring a paste of the info and subsequently save.

For example:
Providing https://pastes.dev/?lang=yaml would automatically select YAML as the language for the paste.