[Feat] Add configurable chord pair margin

[kieraneglin]

What it does

• Adds a plugin configuration option to control the margin between chord pairs

Notes

• This might be niche so no worries if you aren't interested in adding this!
• I keep saying "chord pairs" for lack of a better term, but I don't think that's entirely right. I'm open to suggestions if you'd like me to rename the UI elements
• This plugin is opt-in and by default has no changes for existing users

Screenshots

The plugin settings page

The plugin with spacing set to 0

The plugin with spacing set to 0.5

[jheddings]

I definitely see the value of this... It look like you are effectively adding a padding value between chord pairs. Is that a fair way to look at it? Or maybe you are trying to increase the minimum width of a chord pair?

[kieraneglin]

My original use case was to remove any additional spacing from within a word if there's a chord change over that word. It is purely based on my own visual preference!