Tries to resume a single theme.
If a redirect was provided and a functions.php file was found, we first ensure that functions.php file does not throw fatal errors anymore.
The way it works is by setting the redirection to the error before trying to include the file. If the theme fails, then the redirection will not be overwritten with the success message and the theme will not be resumed.
(string) (Required) Single theme to resume.
(string) (Optional) URL to redirect to.
Default value: ''
(bool|WP_Error) True on success, false if
$theme was not paused,
WP_Error on failure.