Feat: add new words for new audio rate modulations

crates/forth/src/words/sound.rs

@@ -862,6 +862,36 @@ pub(super) const WORDS: &[Word] = &[
         compile: Simple,
         varargs: false,
     },
+    Word {
+        name: "islide",
+        aliases: &[],
+        category: "Audio Modulation",
+        stack: "(start end dur -- str)",
+        desc: "Swell transition (slow start, fast finish): start>end:duri",
+        example: "200 4000 1 islide lpf",
+        compile: Simple,
+        varargs: false,
+    },
+    Word {
+        name: "oslide",
+        aliases: &[],
+        category: "Audio Modulation",
+        stack: "(start end dur -- str)",
+        desc: "Pluck transition (fast attack, slow settle): start>end:duro",
+        example: "0 1 0.5 oslide gain",
+        compile: Simple,
+        varargs: false,
+    },
+    Word {
+        name: "pslide",
+        aliases: &[],
+        category: "Audio Modulation",
+        stack: "(start end dur -- str)",
+        desc: "Stair transition (8 discrete steps): start>end:durp",
+        example: "0 1 2 pslide gain",
+        compile: Simple,
+        varargs: false,
+    },
     Word {
         name: "jit",
         aliases: &[],