fix: set format line separators on save

[JohannesIBK]

Previously, line separators were never formatted and had to be changed manually in the IDE.

[nhedger]

Could you expand a bit on what issue the PR solves?

Also wouldn't this make the CLI and extension formatting inconsistent?

[JohannesIBK]

So basically when using Format on Save, the line separators wouldn't change (Try change the line separators in biome.json and see how the line separators are not changed when saving). This basically correctly sets them and should make the output equal to the CLI output.

[ematipico]

I still don't understand what the issue is. Via configuration, Biome is able to use a different line ending. Why would the extension be in charge of changing that?

[JohannesIBK]

With the current version of the plugin, IntelliJ basically just ignores the line separators returned by Biome. There were two problems with the current implementation:

1. setText(...)` does not change the line breaks, so no matter what the config would be, it would never change the line breaks.
2. The CapturingProcessHandler always replaces the line breaks it reads with LF line breaks.

So this PR fixes the plugin so that even the IDE accepts and correctly sets the line separators returned by Biome.