adding "yml" as a data file extension on top of "yaml" and "json"

Author: EvanLovely

src/PatternLab/PatternData/Rules/PatternInfoListItemsRule.php

@@ -26,7 +26,7 @@ public function __construct($options) {
 		parent::__construct($options);
 
 		$this->depthProp  = 3; // 3 means that depth won't be checked
-		$this->extProp    = "json||yaml";
+		$this->extProp    = "json||yaml||yml";
 		$this->isDirProp  = false;
 		$this->isFileProp = true;
 		$this->searchProp = ".listitems.";

src/PatternLab/PatternData/Rules/PatternInfoRule.php

@@ -26,7 +26,7 @@ public function __construct($options) {
 		parent::__construct($options);
 
 		$this->depthProp  = 3; // 3 means that depth won't be checked
-		$this->extProp    = "json||yaml";
+		$this->extProp    = "json||yaml||yml";
 		$this->isDirProp  = false;
 		$this->isFileProp = true;
 		$this->searchProp = "";

src/PatternLab/PatternData/Rules/PseudoPatternRule.php

@@ -26,7 +26,7 @@ public function __construct($options) {
 		parent::__construct($options);
 
 		$this->depthProp  = 3; // 3 means that depth won't be checked
-		$this->extProp    = "json||yaml";
+		$this->extProp    = "json||yaml||yml";
 		$this->isDirProp  = false;
 		$this->isFileProp = true;
 		$this->searchProp = "~";