fix: clarify language detection explanation in documentation

Author: MR-Addict

docs/src/local/include.md

@@ -4,7 +4,9 @@
 >
 > Support since [v0.2.12](https://github.com/MR-Addict/mdbook-embedify/releases/tag/0.2.12).
 >
-> Language is detected by file extension, which I manually edited from [linguist](https://github.com/github-linguist/linguist/blob/main/lib/linguist/languages.yml). If you find any issues with the language detection, please open an [issue](https://github.com/MR-Addict/mdbook-embedify/issues).
+> Language is detected by file extension, which I manually referred, simplified and extended from [linguist](https://github.com/github-linguist/linguist/blob/main/lib/linguist/languages.yml).
+>
+> If you find any issues with the language detection, please open an [issue](https://github.com/MR-Addict/mdbook-embedify/issues). Currenltly language map is under [languages.json](https://github.com/MR-Addict/mdbook-embedify/blob/main/src/assets/config/languages.json)
 
 The include app is for including source file or wrapped it as markdown code block.