[doc] unspecify EReg.matched on non-existing group

closes #5352

libs

@@ -1 +1 @@
-Subproject commit 0ce9de94f4333e1080ed4a319d7cf402cec8309c
+Subproject commit e71efd46c68468b8225a44dae5a571e3d992670d

std/EReg.hx

@@ -67,7 +67,7 @@ class EReg {
 		`this.matchSub`, and then operates on the String of that operation.
 
 		The index `n` corresponds to the n-th set of parentheses in the pattern
-		of `this` EReg. If no such sub-group exists, an exception is thrown.
+		of `this` EReg. If no such sub-group exists, the result is unspecified.
 
 		If `n` equals 0, the whole matched substring is returned.
 	**/