`ArcanistDoubleQuoteXHPASTLinterRule` gets the following code wrong:
```lang=php
<?php
echo "\$x";
```
The proposed linter fix suggested by `ArcanistDoubleQuoteXHPASTLinterRule` is:
```lang=diff, counterexample
@@ -1,3 +1,3 @@
<?php
-echo "\$foo";
+echo '\$foo';
```
This is incorrect and should instead be:
```lang=diff
@@ -1,3 +1,3 @@
<?php
-echo "\$foo";
+echo '$foo';
```