Add utf-8 comment support (#971)

Author: junxzm1990

apps/nextra/pages/en/build/smart-contracts/book/coding-conventions.mdx

@@ -67,6 +67,7 @@ module 0x1::importer {
 
 - Each module, struct, and public function declaration should be commented.
 - Move has doc comments `///`, regular single-line comments `//`, block comments `/* */`, and block doc comments `/** */`.
+- Starting Aptos CLI 7.4.0, UTF-8 characters are allowed in comments.
 
 ### Comments Example