MINOR Better presentation of extension error message in File and UploadValidator (from r107274)

git-svn-id: svn://svn.silverstripe.com/silverstripe/open/modules/sapphire/trunk@112565 467b73ca-7a2a-4603-9d3b-597d59a354a9

filesystem/File.php

@@ -780,7 +780,7 @@ class File extends DataObject {
 						PR_MEDIUM,
 						'Argument 1: Comma-separated list of valid extensions'
 					),
-					implode(', ',$exts)
+					wordwrap(implode(', ',$exts))
 				);
 				return new ValidationResult(false, $message);
 			}

filesystem/Upload.php

@@ -507,7 +507,7 @@ class Upload_Validator {
 					PR_MEDIUM,
 					'Argument 1: Comma-separated list of valid extensions'
 				),
-				implode(',', $this->allowedExtensions)
+				wordwrap(implode(', ', $this->allowedExtensions))
 			);
 			return false;
 		}