Update environment variable documentation to include frankenphp in the SSL_PRIVATE_KEY_FILE entry, enhancing clarity on supported configurations for HTTPS.

Author: jaydrogers

docs/content/docs/8.reference/1.environment-variable-specification.md

@@ -116,7 +116,7 @@ Setting environment variables all depends on what method you're using to run you
 `SHOW_WELCOME_MESSAGE`<br />*Default: "true"*|Show a helpful welcome message showing container information when the container starts.|all
 `SSL_CERTIFICATE_FILE`<br />*Default: "/etc/ssl/private/self-signed-web.crt"*|Path to public certificate file for HTTPS. You must provide this file otherwise a self-signed key pair will be generated for you.|fpm-nginx,<br />fpm-apache
 `SSL_MODE`<br />*Default: "off"*|Configure how you would like to handle SSL. This can be "off" (HTTP only), "mixed" (HTTP + HTTPS), or "full" (HTTPS only). If you use HTTP, you may need to also change `PHP_SESSION_COOKIE_SECURE`.|fpm-nginx,<br />fpm-apache,<br />unit
-`SSL_PRIVATE_KEY_FILE`<br />*Default: "/etc/ssl/private/self-signed-web.key"*|Path to private key file for HTTPS. You must provide this file otherwise a self-signed key pair will be generated for you.|fpm-nginx,<br />fpm-apache
+`SSL_PRIVATE_KEY_FILE`<br />*Default: "/etc/ssl/private/self-signed-web.key"*|Path to private key file for HTTPS. You must provide this file otherwise a self-signed key pair will be generated for you.|fpm-nginx,<br />fpm-apache, <br />frankenphp
 `UNIT_CERTIFICATE_NAME`<br />*Default: "self-signed-web-bundle"*| Name of your certificate bundle. This is used to configure HTTPS. (<a target="_blank" href="https://unit.nginx.org/configuration/#ssl-tls-configuration">Official Docs</a>)| unit
 `UNIT_CONFIG_DIRECTORY`<br />*Default: "/etc/unit/config.d"*|Path to the Unit configuration directory. Any *.json, *.js, and *.pem files will be loaded into Unit on initialization.| unit
 `UNIT_CONFIG_FILE`<br />*Default: "/etc/unit/config.d/config.json"*|Path to the Unit configuration file. One will be generated automatically by default. (<a target="_blank" href="https://unit.nginx.org/configuration/#">Official Docs</a>)| unit