Copy/Paste ommitting newlines (again)

[silverwind]

STR:

1. Open https://try.gitea.io/silverwind/symlink-test/src/branch/master/.drone.yml
2. Select the first 5 lines of code
3. Copy the code to clipboard
4. Paste it somewhere
5. Observe that empty line 4 is not copied

I recall a6168fa, which ought to have fixed this but it must have regressed recently and 1.16 is also affected. I do not see a literal newline in the HTML on these empty lines anymore while there should be one.

[lunny]

We need a test to prevent that.

[silverwind]

Pretty sure the issue is coming from modules/highlight and it should be pretty easy to add/modify a test there to include empty lines.

[silverwind]

Seems there is still some issue with YAML files at least, it does work correctly with JS files, very weird.