docs: write the AMO description in Markdown

AMO has formatted descriptions as Markdown since March 2025 and shows any
HTML as plain text, so the pasted HTML version showed its tags on the
live listing. The README's description is now Markdown, with gpt and the
template example as inline code.

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>

docs/amo/README.md

@@ -20,36 +20,38 @@ Ask ChatGPT from anywhere in Firefox. Type gpt in the address bar, right-click s
 
 ## Description
 
-AMO accepts a few HTML tags here, such as `<b>`, `<ul>`, `<li>` and `<a>`.
-Anything else, like `<Ctrl>`, shows as plain text, as `<ctrl>-L` does on the
-1.2 listing. Check the preview after saving.
+Since March 2025, AMO formats descriptions as
+[Markdown](https://blog.mozilla.org/addons/2025/03/03/markdown/) and shows any
+HTML as plain text. Plain `<Ctrl>` therefore shows as typed. Check the preview
+after saving.
 
-```html
+```markdown
 Ask ChatGPT from anywhere in Firefox.
 
-<b>Four ways to use it</b>
-<ul>
-<li><b>Address bar:</b> press <Ctrl>+L, type gpt and your question, like "gpt why does my cat knock things over?", and press <Enter>.</li>
-<li><b>Right-click:</b> select text on any page and choose Ask ChatGPT.</li>
-<li><b>Keyboard:</b> select text and press <Alt>+<Shift>+G. With nothing selected, it opens a blank chat.</li>
-<li><b>Toolbar:</b> click the Ask ChatGPT button.</li>
-</ul>
+**Four ways to use it**
+
+- **Address bar:** press <Ctrl>+L, type `gpt` and your question, like `gpt why does my cat knock things over?`, and press <Enter>.
+- **Right-click:** select text on any page and choose Ask ChatGPT.
+- **Keyboard:** select text and press <Alt>+<Shift>+G. With nothing selected, it opens a blank chat.
+- **Toolbar:** click the Ask ChatGPT button.
+
 ChatGPT opens with your text filled in. You may need to sign in to ChatGPT.
 
-<b>Small on purpose</b>
+**Small on purpose**
+
 The whole extension is about 56 KB, with no libraries, no server, no API key and no intermediary, and nothing is reported to us. Firefox opens chatgpt.com directly, and it never makes ChatGPT your default search engine unless you choose to.
 
-<b>Make it yours</b>
-<ul>
-<li>A simple right-click menu, or an advanced one with Explain, Summarize, Debug code and Translate.</li>
-<li>Your own prompt template, like "Explain simply: {query}".</li>
-<li>Open ChatGPT in a new tab, a background tab or a new window.</li>
-<li>Ask for a temporary chat or a web search. These are hints, and ChatGPT decides whether to honour them.</li>
-<li>Add your own search keyword or change the shortcut in Firefox's settings.</li>
-</ul>
+**Make it yours**
+
+- A simple right-click menu, or an advanced one with Explain, Summarize, Debug code and Translate.
+- Your own prompt template, like `Explain simply: {query}`.
+- Open ChatGPT in a new tab, a background tab or a new window.
+- Ask for a temporary chat or a web search. These are hints, and ChatGPT decides whether to honour them.
+- Add your own search keyword or change the shortcut in Firefox's settings.
+
 Search with ChatGPT is an unofficial extension by Zavage Software and isn't affiliated with OpenAI.
 
-<a href="https://git-repos.zavage.net/zavage-software/search-with-chatgpt-powered-by-openai-extension">Source code</a> · <a href="https://zavage-software.com/portfolio/search-with-ChatGPT">Project website</a> · <a href="https://zavage-software.com/contact-us">Feedback or report a bug</a>
+[Source code](https://git-repos.zavage.net/zavage-software/search-with-chatgpt-powered-by-openai-extension) · [Project website](https://zavage-software.com/portfolio/search-with-ChatGPT) · [Feedback or report a bug](https://zavage-software.com/contact-us)
 ```
 
 Update "about 56 KB" when the package size changes noticeably. `npm run build`