Update cli/azd/docs/style-guidelines/guiding-principles.md

Co-authored-by: puicchan <puichan@Microsoft.com>

Author: kristenwomack

cli/azd/docs/style-guidelines/guiding-principles.md

@@ -61,7 +61,7 @@ The Azure Developer CLI (`azd`) follows a systematic approach to command structu
 
 ## Extension Development
 
-For guidelines on developing extensions to `azd`, see [extensions-style-guide.md](extensions-style-guide.md).
+For guidelines on developing extensions to `azd`, see [extensions-style-guide.md](../extensions/extensions-style-guide.md).
 
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