Elaborate on documentation

Author: jasgin

codegen-server/src/main/kotlin/software/amazon/smithy/rust/codegen/server/smithy/Constraints.kt

@@ -103,9 +103,14 @@ fun Shape.isDirectlyConstrained(symbolProvider: SymbolProvider): Boolean =
     }
 
 /**
- * See [Shape.isDirectlyConstrained]
+ * Finds shapes that are directly constrained in validation phase, which means the shape is a:
+ * - [StructureShape] with a required member that does not have a non-null default
+ * - [EnumShape]
+ * - [IntEnumShape]
+ * - [MemberShape] that is required and does not have a non-null default
  *
- * We use this to check for constrained shapes in validation phase because the [SymbolProvider] has not yet been created
+ * We use this rather than [Shape.isDirectlyConstrained] to check for constrained shapes in validation phase because
+ * the [SymbolProvider] has not yet been created
  */
 fun Shape.isDirectlyConstrainedForValidation(): Boolean =
     when (this) {
@@ -160,9 +165,10 @@ fun Shape.canReachConstrainedShape(
     }
 
 /**
- * See [Shape.canReachConstrainedShape]
+ * Whether this shape (or the shape's target for [MemberShape]s) can reach constrained shapes for validations.
  *
- * We use this to check for constrained shapes in validation phase because the [SymbolProvider] has not yet been created
+ * We use this rather than [Shape.canReachConstrainedShape] to check for constrained shapes in validation phase because
+ * the [SymbolProvider] has not yet been created
  */
 fun Shape.canReachConstrainedShapeForValidation(model: Model): Boolean =
     if (this is MemberShape) {

codegen-server/src/main/kotlin/software/amazon/smithy/rust/codegen/server/smithy/util/CustomValidationExceptionUtil.kt

@@ -3,8 +3,10 @@ package software.amazon.smithy.rust.codegen.server.smithy.util
 import software.amazon.smithy.model.shapes.MemberShape
 import software.amazon.smithy.rust.codegen.server.smithy.traits.ValidationMessageTrait
 
-// Helper function to determine if this [MemberShape] is a validation message either explicitly with the
-// @validationMessage trait or implicitly because it is named "message"
+/**
+ * Helper function to determine if this [MemberShape] is a validation message either explicitly with the
+ * @validationMessage trait or implicitly because it is named "message"
+ */
 fun MemberShape.isValidationMessage(): Boolean {
     return this.hasTrait(ValidationMessageTrait.ID) || this.memberName == "message"
 }