Add scaladoc for steps.annotation.toString

src/main/scala/steps/annotation/toString.scala

@@ -3,8 +3,44 @@ package steps.annotation
 import scala.annotation.{experimental, MacroAnnotation}
 import scala.quoted.*
 
+
+/**
+ * A macro annotation that automatically generates a custom `toString` method for a class.
+ * 
+ * The `@toString` annotation can be applied to a class, object, or trait. When applied, it overrides the `toString`
+ * method to include the class name and the values of all fields marked as `ParamAccessor`.
+ * 
+ * If the class already defines or overrides the `toString` method, the annotation will emit a warning indicating that
+ * the annotation is not necessary. The existing `toString` method will remain unchanged.
+ *
+ * Example usage:
+ * {{{
+ * @toString
+ * class MyClass(val a: Int, val b: String)
+ *
+ * val instance = MyClass(1, "hello")
+ * println(instance.toString) // Output: MyClass(1, hello)
+ * }}}
+ *
+ * The generated `toString` method produces output in the format: `ClassName(field1, field2, ...)`.
+ *
+ * @note This annotation requires Scala's `experimental` flag to be enabled, or it can be used within a scope
+ *       marked as experimental (i.e., using `import scala.annotation.experimental`). This is necessary because it 
+ *       relies on experimental macro annotation features.
+ */
 @experimental
 final class toString extends MacroAnnotation:
+
+  /**
+   * Transforms the annotated class to add a custom `toString` method.
+   * 
+   * If the class already overrides `toString`, a warning is emitted and no changes are made.
+   * Otherwise, this annotation adds a new `toString` method that returns a string representation of
+   * the class name and its fields.
+   * 
+   * @param tree The abstract syntax tree (AST) of the annotated class, object, or trait.
+   * @return The transformed class definition, with the generated `toString` method if applicable.
+   */
   override def transform(using Quotes)(tree: quotes.reflect.Definition): List[quotes.reflect.Definition] = 
     import quotes.reflect.*
     val toStringSym = Symbol.requiredMethod("java.lang.Object.toString")
@@ -38,6 +74,15 @@ final class toString extends MacroAnnotation:
         report.errorAndAbort("@toString is only supported in class/object/trait")
   end transform
 
+  /**
+   * Helper method to create the string representation of the class.
+   *
+   * Constructs a string in the format: `ClassName(field1, field2, ...)`.
+   *
+   * @param className The name of the class.
+   * @param thisFields The list of expressions representing the class fields.
+   * @return A quoted expression representing the final string.
+   */
   private def toStringExpr(className: String, thisFields: List[Expr[Any]])(using Quotes): Expr[String] =
     val fieldsSeq = Expr.ofSeq(thisFields)
     val prefix = Expr(className + "(")