Stop website examples from linking to old URL with multiple redirects (…

…bevyengine#14500)

# Objective

Fixes bevyengine/bevy-website#1558
Followup to bevyengine#12348 

For the website pages extra link, it needs kebab case for the category
name and a trailing forward slash to make the link for the Bevy website
correct and not have unnecessary redirections.

## Solution

Changes the category name to kebab case for the extra link, and adds a
trailing forward slash to the link.

## Testing

I have tested these changes.

Clone my fork with the changes in `bevy-website/generate-wasm-examples/`
then `cd bevy && git switch bevy-website/1558_fix_beautify_example_links
&& cd ..` and then `./generate_wasm_examples.sh` to generate examples.

Afterwards runs `zola serve` and go to `http://127.0.0.1:1111/examples`
and hover over or inspect the cards links / anchors to see that the link
is now correct, click on any of the cards to see that there is no
redirects.

tools/example-showcase/src/main.rs

@@ -502,18 +502,18 @@ header_message = \"Examples (WebGL2)\"
  continue;
  }
 
- // This beautifys the path
+ // This beautifys the category name
  // to make it a good looking URL
  // rather than having weird whitespace
  // and other characters that don't
  // work well in a URL path.
- let category_path = root_path.join(
- to_show
-  .category
-  .replace(['(', ')'], "")
-  .replace(' ', "-")
- .to_lowercase(),
- );
+ let beautified_category = to_show
+ .category
+ .replace(['(', ')'], "")
+ .replace(' ', "-")
+ .to_lowercase();
+
+ let category_path = root_path.join(&beautified_category);
 
  if !categories.contains_key(&to_show.category) {
  let _ = fs::create_dir_all(&category_path);
@@ -556,7 +556,7 @@ aliases = [\"/examples{}/{}/{}\"]
 
 [extra]
 technical_name = \"{}\"
-link = \"/examples{}/{}/{}\"
+link = \"/examples{}/{}/{}/\"
 image = \"../static/screenshots/{}/{}.png\"
 code_path = \"content/examples{}/{}\"
 shader_code_paths = {:?}
@@ -581,7 +581,7 @@ header_message = \"Examples ({})\"
  WebApi::Webgpu => "-webgpu",
  WebApi::Webgl2 => "",
  },
- &to_show.category,
+ &beautified_category,
  &to_show.technical_name.replace('_', "-"),
  &to_show.category,
  &to_show.technical_name,