chore(multi-select): keep checkboxes rendered in DOM

Display ListBox via CSS

docs/src/COMPONENT_API.json

@@ -7007,7 +7007,7 @@
           "name": "itemToInput",
           "kind": "let",
           "description": "Override the item name, title, labelText, or value passed to the user-selectable checkbox input as well as the hidden inputs.",
-          "type": "(item: MultiSelectItem) => { name?: string; labelText?: any; title?:\nstring; value?: string }",
+          "type": "(item: MultiSelectItem) => { name?: string; labelText?: any; title?: string; value?: string }",
           "value": "(item) => {}",
           "isFunction": true,
           "isFunctionDeclaration": false,
@@ -7015,30 +7015,6 @@
           "constant": false,
           "reactive": false
         },
-        {
-          "name": "selectedOnly",
-          "kind": "let",
-          "description": "Set to `true` to only render selected options as hidden inputs for form submission.",
-          "type": "boolean",
-          "value": "false",
-          "isFunction": false,
-          "isFunctionDeclaration": false,
-          "isRequired": false,
-          "constant": false,
-          "reactive": false
-        },
-        {
-          "name": "combineValues",
-          "kind": "let",
-          "description": "Combine selected items as comma-separated values when submitted in a form.\nIf set to `true`, the default separator is a comma `,`.\nPass in a string to override the separator.",
-          "type": "false | true | string",
-          "value": "false",
-          "isFunction": false,
-          "isFunctionDeclaration": false,
-          "isRequired": false,
-          "constant": false,
-          "reactive": false
-        },
         {
           "name": "selectedIds",
           "kind": "let",

docs/src/pages/components/MultiSelect.svx

@@ -14,10 +14,9 @@
 By default, items will be ordered alphabetically based on the `item.text` value.
 To prevent this, see [#no-alphabetical-ordering](#no-alphabetical-ordering).
 
-Hidden inputs will be rendered based on user selection, such as `<input type="hidden"
-name="0" value="true" />` to mirror checkbox values and to allow MultiSelect to
-be submittable within forms. These hidden inputs can be customized with
-the `combineValues` or `itemToInput` props.
+MultiSelect provides interactivity for a list of checkbox inputs. Those
+checkboxes will remain rendered in the DOM and are submittable within forms.
+Checkbox attributes can be adjusted via the `itemToInput` prop.
 
 <MultiSelect titleText="Contact" label="Select contact methods..."
     items="{[{id: "0", text: "Slack"},
@@ -96,30 +95,8 @@ The above function sets the `name` attribute to
 `Contact_0` (respective to each item's `id`) for every hidden input that
 renders, along with each respective item's `id` set to the `value` attribute.
 
-When using with the `selectedOnly` prop, you can override every hidden input to
-use the same `name` attribute. This may be useful if you
-wish to use `formData.getAll('contact')` in your server-side form handler.
-
 <MultiSelect
   itemToInput={(item) => ({name: 'contact', value: item.id})}
-  selectedOnly
-  titleText="Contact"
-  label="Select contact methods..."
-  items="{[
-    {id: "0", text: "Slack"},
-    {id: "1", text: "Email"},
-    {id: "2", text: "Fax"}
-  ]}"
-/>
-
-## Combine values into a single input
-
-With the `combineValues` prop, all selected items' values will render as a
-comma-separated string within a single hidden input. A custom delimiter can
-alternatively be passed in.
-
-<MultiSelect
-  combineValues
   titleText="Contact"
   label="Select contact methods..."
   items="{[