Add link from coding guideline issue template to formatting guide#199

PLeVasseur wants to merge 2 commits intorustfoundation:mainrustfoundation/safety-critical-rust-coding-guidelines:mainfrom

PLeVasseur:feature/update-coding-guideline-issue-template-link-to-formatting-guidePLeVasseur/safety-critical-rust-coding-guidelines:feature/update-coding-guideline-issue-template-link-to-formatting-guideCopy head branch name to clipboard