[Speed] Update content-encoding-issues.mdx (#26676)

Can we remove Mirage? 

Its not longer available in the UI.

Thanks.

Author: nenizera

src/content/docs/speed/optimization/content/troubleshooting/content-encoding-issues.mdx

@@ -13,7 +13,6 @@ You also have the option to turn off these features site-wide within the dashboa
 
 - [Email Obfuscation](/waf/tools/scrape-shield/email-address-obfuscation/), located in the **Scrape Shield** section.
 - [Rocket Loader](/speed/optimization/content/rocket-loader/), located in **Speed** > **Settings** > **Content Optimization** section.
-- [Mirage](/speed/optimization/images/mirage/) (deprecated), located in **Speed** > **Settings** > **Image Optimization**. section.
 - [Automatic HTTPS Rewrites](/ssl/edge-certificates/additional-options/automatic-https-rewrites/), located in the **SSL/TLS** > **Edge Certificates** section.
 
 Misconfiguring the `Content-Type` or charset within HTML, or leaving them unspecified can lead to unintended consequences. This can disrupt the intended content presentation, resulting in disorganized rendering and potentially unclear characters. Properly configuring these elements ensures consistent and accurate interpretation, correct HTML modifications, and accurate rendering for browsers. This creates a seamless user experience and aligns with best practices in web development.