Remove trailing whitespace

Co-authored-by: dmalan <[email protected]>

Author: Copilot

lib/jekyll-theme-cs50.rb

@@ -105,7 +105,7 @@ def describe(input, max_length = 160)
       return "" if input.nil? || input.to_s.strip.empty?
 
       markdown = input.to_s
-      
+
       # Render Liquid tags first if $site is defined
       if defined?($site) && $site
         begin