add repository link entry

Author: Young-Flash

.github/ISSUE_TEMPLATE/bug_report.md

@@ -24,6 +24,8 @@ Otherwise please try to provide information which will help us to fix the issue
 
 **relevant settings**: (eg. client settings, or environment variables like `CARGO`, `RUSTC`, `RUSTUP_HOME` or `CARGO_HOME`)
 
+**repository link (if public, optional)**: (eg. [rust-analyzer](https://github.com/rust-lang/rust-analyzer))
+
 **code snippet to reproduce**: 
 ```rust
 // add your code here