Docs, part 3 (#415)

* Add docs to SkipOnErrorInterface

* Add docs to SkipOnErrorTrait

* Update src/Rule/Trait/SkipOnErrorTrait.php

Co-authored-by: Alexander Makarov <sam@rmcreative.ru>

* Update src/SkipOnErrorInterface.php

Co-authored-by: Alexander Makarov <sam@rmcreative.ru>

* Fix linebreak

Co-authored-by: Alexander Makarov <sam@rmcreative.ru>

src/Rule/Trait/SkipOnErrorTrait.php

@@ -4,15 +4,42 @@
 
 namespace Yiisoft\Validator\Rule\Trait;
 
+/**
+ * An implementation for {@see SkipOnErrorInterface} intended to be included in rules. Requires an additional private
+ * class property `$skipOnError`. In package rules it's `false` by default:
+ *
+ * ```php
+ * public function __construct(
+ *     // ...
+ *     private bool $skipOnError = false,
+ *     // ...
+ * ) {
+ * }
+ * ```
+ */
 trait SkipOnErrorTrait
 {
+    /**
+     * An immutable setter to change `$skipOnError` property.
+     *
+     * @param bool $value A new value. `true` means to skip the current rule when the previous one errored and `false` -
+     * do not skip.
+     *
+     * @return $this The new instance with a changed value.
+     */
     public function skipOnError(bool $value): static
     {
         $new = clone $this;
         $new->skipOnError = $value;
         return $new;
     }
 
+    /**
+     * A getter for `$skipOnError` property.
+     *
+     * @return bool Current value. `true` means to skip the current rule when the previous one errored  and `false` - do
+     * not skip.
+     */
     public function shouldSkipOnError(): bool
     {
         return $this->skipOnError;

src/SkipOnErrorInterface.php

@@ -4,9 +4,32 @@
 
 namespace Yiisoft\Validator;
 
+use Yiisoft\Validator\Rule\Trait\SkipOnErrorTrait;
+
+/**
+ * An optional interface for rules to implement. It allows skipping validation for a rule within a group of other rules
+ * if a previous rule (not the current one!) did not pass the validation.
+ *
+ * The package ships with {@see SkipOnErrorTrait} which already implements that interface. All you have to do is include
+ * it in the rule class along with the interface.
+ */
 interface SkipOnErrorInterface
 {
+    /**
+     * Changes current "skip on error" value. Must be immutable.
+     *
+     * @param bool $value A new value. `true` means to skip the current rule when the previous one errored and `false` -
+     * do not skip.
+     *
+     * @return $this The new instance of a rule with a changed value.
+     */
     public function skipOnError(bool $value): static;
 
+    /**
+     * Returns current "skip on error" value.
+     *
+     * @return bool Current value. `true` means to skip the current rule when the previous one errored  and `false` - do
+     * not skip.
+     */
     public function shouldSkipOnError(): bool;
 }