This is a very simple extension that does one thing. It will swap single quotes to double quotes and vice versa.
Let's say you have the following code.
<?php
$text = 'Click me';
$button_html = '<div class="btn">{$text}</div>';
//_____________^___________^__^____🤦________^And you want php to parse the variable $text inside the double quotes. You can do it by swapping the quotes.
Run the command "Swap Quotes" from the command palette and you will get:
<?php
$text = 'Click me';
$button_html = "<div class='btn'>{$text}</div>";
//_____________^___________^__^____🥳________^Enjoy!