The line 154 in \includes\recaptcha.php just says:
$reCaptcha = new \ReCaptcha\ReCaptcha($secret);
It’s a simple call to the Official Google Recaptcha Class and the error you describes it be often related with “a PHPH syntax errors”.
I’m sorry but without more clues about your installation environment, I just can suppose that there has been an error during the installation and one or more files are corrupted.
Please, check the integrity of this file, and if you detect any suspicious line, the best way is to delete manually all files in the plugin’s folder
wp-content\plugins\recaptcha-in-wp-comments-form\
afterwards, delete the folder and reinstall a new clean download file of the plugin.
Thanks in advance,
Joan Miquel
