feat(kakaotalk): Add KotlinUnitInstanceFingerprint for ghost mode patch

patches/src/main/kotlin/app/revanced/patches/kakaotalk/common/fingerprints/KotlinUnitInstanceFingerprint.kt

@@ -0,0 +1,19 @@
+package app.revanced.patches.kakaotalk.common.fingerprints
+
+import app.revanced.patcher.fingerprint
+import com.android.tools.smali.dexlib2.AccessFlags
+import com.android.tools.smali.dexlib2.Opcode
+
+internal val kotlinUnitInstanceFingerprint = fingerprint {
+    accessFlags(AccessFlags.PUBLIC, AccessFlags.FINAL)
+    parameters()
+    returns("Ljava/lang/String;")
+    strings("kotlin.Unit")
+    opcodes(
+        Opcode.CONST_STRING,
+        Opcode.RETURN_OBJECT
+    )
+    custom { method, classDef ->
+        method.name == "toString"
+    }
+}

patches/src/main/kotlin/app/revanced/patches/kakaotalk/ghost/GhostModePatch.kt

@@ -2,6 +2,7 @@ package app.revanced.patches.kakaotalk.ghost
 
 import app.revanced.patcher.extensions.InstructionExtensions.addInstructions
 import app.revanced.patcher.patch.bytecodePatch
+import app.revanced.patches.kakaotalk.common.fingerprints.kotlinUnitInstanceFingerprint
 import app.revanced.patches.kakaotalk.ghost.fingerprints.ghostModeFingerprint
 
 @Suppress("unused")
@@ -12,12 +13,17 @@ val ghostMode = bytecodePatch(
     compatibleWith("com.kakao.talk"("25.4.0"))
 
     execute {
+        val findUnit = kotlinUnitInstanceFingerprint.method
+        val unitClass = findUnit.definingClass
+
         val method = ghostModeFingerprint.method
 
+        // I tried to find the field name, but it's pretty obvious to me, so I hardcode it.
+        // If it changes, we need to fix it
         method.addInstructions(
             0,
             """
-                sget-object v0, Lnk0/C;->a:Lnk0/C;
+                sget-object v0, $unitClass->a:$unitClass;
                 return-object v0
             """.trimIndent()
         )