Update hbs_renderer.rs

Author: expikr

src/renderer/html_handlebars/hbs_renderer.rs

@@ -702,9 +702,9 @@ fn make_data(
     if !html_config.additional_theme.is_empty() {
         let mut theme = Vec::new();
         for name in &html_config.additional_theme {
-            match name.strip_prefix(root) {
-                Ok(p) => theme.push(p.to_str().expect("Could not convert to str")),
-                Err(_) => theme.push(name.to_str().expect("Could not convert to str")),
+            match name {
+                Ok(p) => theme.push(p.to_lowercase()),
+                Err(_) => theme.push(name.to_lowercase()),
             }
         }
         data.insert("additional_theme".to_owned(), json!(theme));