Document list/map/array constructor data binding

Closes gh-32426

framework-docs/modules/ROOT/pages/core/validation/beans-beans.adoc

@@ -27,15 +27,20 @@ The target class should have a single public constructor or a single non-public
 with arguments. If there are multiple constructors, then a default constructor if present
 is used.
 
-By default, constructor parameter names are used to look up argument values, but you can
-configure a `NameResolver`. Spring MVC and WebFlux both rely to allow customizing the name
-of the value to bind through an `@BindParam` annotation on constructor parameters.
+By default, argument values are looked up via constructor parameter names. Spring MVC and
+WebFlux support a custom name mapping through the `@BindParam` annotation on constructor
+parameters or fields if present. If necessary, you can also configure a `NameResolver` on
+`DataBinder` to customize the argument name to use.
 
 xref:beans-beans-conventions[Type conversion] is applied as needed to convert user input.
 If the constructor parameter is an object, it is constructed recursively in the same
 manner, but through a nested property path. That means constructor binding creates both
 the target object and any objects it contains.
 
+Constructor binding supports `List`, `Map`, and array arguments either converted from
+a single string, e.g. comma-separated list, or based on indexed keys such as
+`accounts[2].name` or `account[KEY].name`.
+
 Binding and conversion errors are reflected in the `BindingResult` of the `DataBinder`.
 If the target is created successfully, then `target` is set to the created instance
 after the call to `construct`.
@@ -90,13 +95,12 @@ details. The below table shows some examples of these conventions:
 | Indicates the nested property `name` of the property `account` that corresponds to
   (for example) the `getAccount().setName()` or `getAccount().getName()` methods.
 
-| `account[2]`
+| `accounts[2]`
 | Indicates the _third_ element of the indexed property `account`. Indexed properties
   can be of type `array`, `list`, or other naturally ordered collection.
 
-| `account[COMPANYNAME]`
-| Indicates the value of the map entry indexed by the `COMPANYNAME` key of the `account` `Map`
-  property.
+| `accounts[KEY]`
+| Indicates the value of the map entry indexed by the `KEY` value.
 |===
 
 (This next section is not vitally important to you if you do not plan to work with

framework-docs/modules/ROOT/pages/web/webflux/controller/ann-methods/modelattrib-method-args.adoc

@@ -81,6 +81,10 @@ NOTE: The `@BindParam` may also be placed on the fields that correspond to const
 parameters. While `@BindParam` is supported out of the box, you can also use a
 different annotation by setting a `DataBinder.NameResolver` on `DataBinder`
 
+Constructor binding supports `List`, `Map`, and array arguments either converted from
+a single string, e.g. comma-separated list, or based on indexed keys such as
+`accounts[2].name` or `account[KEY].name`.
+
 WebFlux, unlike Spring MVC, supports reactive types in the model, e.g. `Mono<Account>`.
 You can declare a `@ModelAttribute` argument with or without a reactive type wrapper, and
 it will be resolved accordingly to the actual value.

framework-docs/modules/ROOT/pages/web/webmvc/mvc-controller/ann-methods/modelattrib-method-args.adoc

@@ -116,6 +116,10 @@ NOTE: The `@BindParam` may also be placed on the fields that correspond to const
 parameters. While `@BindParam` is supported out of the box, you can also use a
 different annotation by setting a `DataBinder.NameResolver` on `DataBinder`
 
+Constructor binding supports `List`, `Map`, and array arguments either converted from
+a single string, e.g. comma-separated list, or based on indexed keys such as
+`accounts[2].name` or `account[KEY].name`.
+
 In some cases, you may want access to a model attribute without data binding. For such
 cases, you can inject the `Model` into the controller and access it directly or,
 alternatively, set `@ModelAttribute(binding=false)`, as the following example shows: