Add stable IDs to the plugin's enum parameters

Existing instances will automatically be upgraded to these IDs when the
instance gets saved. This makes it possible to rearrange things later
when needed.

plugins/puberty_simulator/src/lib.rs

@@ -86,10 +86,12 @@ struct PubertySimulatorParams {
 enum PitchShiftingMode {
     /// Directly linearly interpolate sine and cosine waves from different bins. This obviously
     /// sounds very bad, but it also sounds kind of hilarious.
+    #[id = "interpolated-rectangular"]
     #[name = "Very broken"]
     InterpolateRectangular,
     /// The same as `InterpolateRectangular`, but interpolating the polar forms instead. This sounds
     /// slightly better, which actually ends up making it sound a lot worse.
+    #[id = "interpolated-polar"]
     #[name = "Also very broken"]
     InterpolatePolar,
 }