Add docs about ResetButton widget (#125)

README.md

@@ -45,6 +45,7 @@ The following documentation describes how to use widgets with PHP:
 - [Radio](docs/radio.md)
 - [RadioList](docs/radiolist.md)
 - [Range](docs/range.md)
+- [ResetButton](docs/resetbutton.md)
 - [SubmitButton](docs/submitbutton.md)
 - [Text](docs/text.md)  
 - [Telephone](docs/telephone.md)

docs/resetbutton.md

@@ -0,0 +1,51 @@
+# Reset button widget
+
+[ResetButton](https://www.w3.org/TR/2012/WD-html-markup-20120329/input.reset.html#input.reset) represents a button for resetting a form.
+
+## Usage
+
+Widget view:
+
+```php
+<?php
+
+declare(strict_types=1);
+
+use Yiisoft\Form\Widget\Field;
+use Yiisoft\Form\Widget\Form;
+use Yiisoft\Form\Widget\ResetButton;
+
+/**
+ * @var object $csrf
+ */
+?>
+
+<?= Form::widget()->action('widgets')->csrf($csrf)->begin(); ?>
+    <?= ResetButton::widget()->value('Reset Form'); ?>
+    <hr class="mt-3">
+    <?= Field::widget()->submitButton(['class' => 'button is-block is-info is-fullwidth', 'value' => 'Save']); ?>
+<?= Form::end(); ?>
+```
+
+That would generate the following code:
+
+```html
+<form action="widgets" method="POST" _csrf="LB8wetUt2ESCosrpbO1wsJEj1UQMxhK9RPyY0wExq9lIckEo50GbJbbT860zgACCy1C-aTWNfs50kcybWELGlQ==">
+    <input type="hidden" name="_csrf" value="LB8wetUt2ESCosrpbO1wsJEj1UQMxhK9RPyY0wExq9lIckEo50GbJbbT860zgACCy1C-aTWNfs50kcybWELGlQ==">
+    <input type="reset" id="reset-10194484223001" name="reset-10194484223001" value="Reset Form">
+    <hr class="mt-3">
+    <div>
+        <input type="submit" id="submit-10194493875001" class="button is-block is-info is-fullwidth" name="submit-10194493875001" value="Save">
+    </div>
+</form>
+```
+
+### `Common` methods:
+
+Method | Description | Default
+-------|-------------|---------
+`autoIdPrefix(string $value)` | Sets the prefix for generating automatic IDs | `'reset-'`
+`attributes(array $value)` | Sets the HTML attributes | `[]``
+`id(string $id)` | Sets the ID attribute | `''`
+`name(string $name)` | Sets the name attribute | `''`
+`value(string $value)` | Sets the value attribute | `''`