[IR] Add a kDoc for IrStringConcatenation

compiler/ir/ir.tree/gen/org/jetbrains/kotlin/ir/expressions/IrStringConcatenation.kt

@@ -13,7 +13,16 @@ import org.jetbrains.kotlin.ir.visitors.IrElementTransformer
 import org.jetbrains.kotlin.ir.visitors.IrElementVisitor
 
 /**
- * A leaf IR tree element.
+ * Represents a string template expression.
+ *
+ * For example, the value of `template` in the following code:
+ * ```kotlin
+ * val i = 10
+ * val template = "i = $i"
+ * ```
+ * will be represented by [IrStringConcatenation] with the following list of [arguments]:
+ * - [IrConst] whose `value` is `"i = "`
+ * - [IrGetValue] whose `symbol` will be that of the `i` variable. 
  *
  * Generated from: [org.jetbrains.kotlin.ir.generator.IrTree.stringConcatenation]
  */

compiler/ir/ir.tree/tree-generator/src/org/jetbrains/kotlin/ir/generator/IrTree.kt

@@ -1102,6 +1102,19 @@ object IrTree : AbstractTreeBuilder() {
     val stringConcatenation: Element by element(Expression) {
         parent(expression)
 
+        kDoc = """
+        Represents a string template expression.
+        
+        For example, the value of `template` in the following code:
+        ```kotlin
+        val i = 10
+        val template = "i = ${'$'}i"
+        ```
+        will be represented by [${typeName}] with the following list of [arguments]:
+        - [${const.typeName}] whose `value` is `"i = "`
+        - [${getValue.typeName}] whose `symbol` will be that of the `i` variable. 
+        """.trimIndent()
+
         +listField("arguments", expression, mutability = MutableList)
     }
     val suspensionPoint: Element by element(Expression) {