[docs] Add ltchiptool GUI download button

docs/flashing/tools/ltchiptool.md

@@ -14,6 +14,11 @@
 
 ## Installation
 
+<div align="center" markdown>
+
+[:material-download-outline: Download GUI](https://github.com/libretuya/ltchiptool/releases/latest){ .md-button }
+</div>
+
 ### GUI package (Windows only)
 
 Download the latest release .EXE from the [GitHub Releases page](https://github.com/libretuya/ltchiptool/releases/latest). Open the file, and you're ready to go!

mkdocs.yml

@@ -33,6 +33,10 @@ plugins:
 markdown_extensions:
   - md_in_html
   - admonition
+  - attr_list
+  - pymdownx.emoji:
+      emoji_index: !!python/name:materialx.emoji.twemoji
+      emoji_generator: !!python/name:materialx.emoji.to_svg
   - pymdownx.highlight:
       anchor_linenums: true
   - pymdownx.inlinehilite