[TASK] Deprecate ::atRuleArgs()

These methods

- are not used internally
- are redundant to the existing getters
- have wildly different return types across classes, which
  reduces the usefulness of the general method

Author: oliverklee

CHANGELOG.md

@@ -30,6 +30,7 @@ This project adheres to [Semantic Versioning](https://semver.org/).
 
 ### Deprecated
 
+- Deprecate `::atRuleArgs()` (#1191)
 - Passing a `string` or `null` to `RuleSet::removeRule()` is deprecated
   (implementing classes are `AtRuleSet` and `DeclarationBlock`);
   use `removeMatchingRules()` or `removeAllRules()` instead (#1249)

src/CSSList/AtRuleBlockList.php

@@ -42,6 +42,8 @@ public function atRuleName()
 
     /**
      * @return string
+     *
+     * @deprecated since V8.9.0, will be removed in version 9.0.0. Use the specific getter instead.
      */
     public function atRuleArgs()
     {

src/CSSList/KeyFrame.php

@@ -101,6 +101,8 @@ public function atRuleName()
 
     /**
      * @return string|null
+     *
+     * @deprecated since V8.9.0, will be removed in version 9.0.0. Use the specific getter instead.
      */
     public function atRuleArgs()
     {

src/Property/AtRule.php

@@ -33,6 +33,8 @@ public function atRuleName();
 
     /**
      * @return string|null
+     *
+     * @deprecated since V8.8.0, will be removed in version 9.0.0. Use the specific getter(s) instead.
      */
     public function atRuleArgs();
 }

src/Property/CSSNamespace.php

@@ -116,6 +116,8 @@ public function atRuleName()
 
     /**
      * @return array<int, string>
+     *
+     * @deprecated since V8.8.0, will be removed in version 9.0.0. Use the specific getters instead.
      */
     public function atRuleArgs()
     {

src/Property/Charset.php

@@ -99,6 +99,8 @@ public function atRuleName()
 
     /**
      * @return string
+     *
+     * @deprecated since V8.9.0, will be removed in version 9.0.0. Use the specific getter instead.
      */
     public function atRuleArgs()
     {

src/Property/Import.php

@@ -94,6 +94,8 @@ public function atRuleName()
 
     /**
      * @return array<int, URL|string>
+     *
+     * @deprecated since V8.8.0, will be removed in version 9.0.0. Use the specific getters instead.
      */
     public function atRuleArgs()
     {

src/RuleSet/AtRuleSet.php

@@ -45,6 +45,8 @@ public function atRuleName()
 
     /**
      * @return string
+     *
+     * @deprecated since V8.9.0, will be removed in version 9.0.0. Use the specific getter instead.
      */
     public function atRuleArgs()
     {