feat(formItem): Change slot label formItem to scopedSlots (#2522)

* Change slot label from formItem to scoupedSlot

* Improve docs with scoped value

* Update documentation for scopedSlots on FormItem

packages/form/src/form-item.vue

@@ -13,7 +13,9 @@
         class="el-form-item__label"
         :style="labelStyle"
       >
-        <slot name="label">{{ label + elForm.labelSuffix }}</slot>
+        <slot name="label" :label="label + elForm.labelSuffix">
+          {{ label + elForm.labelSuffix }}
+        </slot>
       </label>
     </LabelWrap>
     <div class="el-form-item__content" :style="contentStyle">

website/docs/en-US/form.md

@@ -644,11 +644,11 @@ All components in a Form inherit their `size` attribute from that Form. Similarl
 | Name | Description |
 |------|--------|
 | — | content of Form Item |
-| label | content of label |
 
 ### Form-Item Scoped Slot
 |      Name     | Description |
 |---------------|-------------|
+| label | Custom content to display on label. The scope parameter is { label } |
 |      error    | Custom content to display validation message. The scope parameter is { error } |
 
 ### Form-Item Methods

website/docs/es/form.md

@@ -661,12 +661,12 @@ Todos los componentes de un formulario heredan su atributo `size`. De manera sim
 | Nombre | Descripción              |
 | ------ | ------------------------ |
 | —      | contenido del Form Item  |
-| label  | contenido de la etiqueta |
 
 ### Form-Item Scoped Slot
 
 | Name  | Description                                                  |
 | ----- | ------------------------------------------------------------ |
+| label | Custom content to display on label. The scope parameter is { label } |
 | error | Contenido personalizado para mostrar el mensaje de validación. El parámetro del scope es { error } |
 
 ### Form-Item Metodo

website/docs/fr-FR/form.md

@@ -644,11 +644,11 @@ Tout les composants d'un formulaire héritent leur attribut `size` de ce formula
 | Nom | Description |
 |------|--------|
 | — | Contenu de Form Item. |
-| label | Contenu du label. |
 
 ### Slot avec portée de Form-Item
 |      Nom     | Description |
 |---------------|-------------|
+| label | Custom content to display on label. The scope parameter is { label } |
 |      error    | Contenu personnalisé pour les messages de validation. Le paramètre du scope est { error }. |
 
 ### Méthodes de Form-Item

website/docs/jp/form.md

@@ -645,11 +645,11 @@ The component has been upgraded with a flex layout to replace the old float layo
 | Name | Description |
 |------|--------|
 | — | フォームアイテムの内容 |
-| label | ラベルの内容 |
 
 ### フォームアイテムのスコープスロット
 |      Name     | Description |
 |---------------|-------------|
+| label | Custom content to display on label. The scope parameter is { label } |
 |      error    | Custom content to display validation message. The scope parameter is { error } |
 
 ### フォームアイテムのメソッド

website/docs/zh-CN/form.md

@@ -639,11 +639,11 @@ W3C 标准中有如下[规定](https://www.w3.org/MarkUp/html-spec/html-spec_8.h
 | name | 说明 |
 |------|--------|
 | — | Form Item 的内容 |
-| label | 标签文本的内容 |
 
 ### Form-Item Scoped Slot
 |  name  |   说明  |
 |--------|--------|
+| label | Custom content to display on label. The scope parameter is { label } |
 |  error | 自定义表单校验信息的显示方式，参数为 { error } |
 
 ### Form-Item Methods