How to show some text below a post if it has a certain tag

We needed to show a given text on some of our blog posts because they contained useful php code snippets.

Our users can hire us to potentially customize the snippets for them.

We've just added a tag called "snippets" to the posts that have at least one snippet.
The code below checks if a post has it and our desired text will be displayed.

Make sure you edit this snippet and replace "ENTER-YOUR-TAG-HERE" with the tag of your choice.

We're using this snippet as a system plugin (installed in wp-content/mu-plugins/)

<?php

// Hook into the_content
add_filter('the_content', 'orb_render_text_cta', 100);


/**
 * Code downloaded from https://orbisius.com/p4298
 * @param string $content
 * @return string
 * @see https://wordpress.stackexchange.com/questions/51732/what-filters-are-applied-to-the-content-function
 */
function orb_render_text_cta($content) {
	if (empty($_SERVER['REQUEST_URI'])) {
		return $content;
	}

	if ( is_singular()
	     && is_main_query()
	     && has_tag('ENTER-YOUR-TAG-HERE')
	) {		
		$content .= "
";
		$content .= "Some text to be shown if the current post has a given tag";
		$content .= "
";
	}

	return $content;
}