Multi-line JVM Argument Editing

[JamesYeoman]

Is your feature request related to a problem? Please describe. JVM arguments are great for fine-tuning a minecraft installation to squeeze that little bit of stability and performance out of it. However, a lot of launchers, including the vanilla launcher, only have single-line editing. To add insult to injury, that single line doesn't even have a scrollbar. The Technicpack Launcher provides multi-line JVM argument editing (however lacks scrolling, but it's a step in the right direction).

Describe the solution you'd like Ideally, a JVM argument input field similar to that in the Technicpack Launcher, but with scrolling capabilities too. As an MVP though, a simple JVMArgs.txt file that is read and ignores newlines would suffice.

Describe alternatives you've considered I've considered copying to a text file, splitting the single line out into multiple lines, and tweaking that way, but it's overly tedious and ends up being more hassle than just editing in the single-line input.

Additional context N/A

[Ladvace]

this is a feature we can consider adding