refactoring for turning // comments to /**

<!-- 🚨 STOP 🚨 𝗦𝗧𝗢𝗣 🚨 𝑺𝑻𝑶𝑷 🚨 Half of all issues filed here are duplicates, answered in the FAQ, or not appropriate for the bug tracker. Please read the FAQ first, especially the "Common Feature Requests" section. --> ## Search Terms https://github.com/Microsoft/TypeScript/search?q=refactoring+comments&type=Issues ## Suggestion Turn a selected block of double-slash comments to a slash-star-star comments. ## Use Cases Turning conventional `//` into JSDoc