docs: improve README.md formatting and readability (#7376)

- Split long line for better readability
- Add consistent spacing between sections
- Remove extra blank lines
- Update sing-box link to point to main repo instead of releases

Author: aleksandr-miheichev

README.md

@@ -1,16 +1,18 @@
 # v2rayN
-A GUI client for Windows, Linux and macOS, support [Xray](https://github.com/XTLS/Xray-core) and [sing-box](https://github.com/SagerNet/sing-box/releases) and [others](https://github.com/2dust/v2rayN/wiki/List-of-supported-cores)
 
+A GUI client for Windows, Linux and macOS, support [Xray](https://github.com/XTLS/Xray-core)
+and [sing-box](https://github.com/SagerNet/sing-box)
+and [others](https://github.com/2dust/v2rayN/wiki/List-of-supported-cores)
 
 [![GitHub commit activity](https://img.shields.io/github/commit-activity/m/2dust/v2rayN)](https://github.com/2dust/v2rayN/commits/master)
 [![CodeFactor](https://www.codefactor.io/repository/github/2dust/v2rayn/badge)](https://www.codefactor.io/repository/github/2dust/v2rayn)
 [![GitHub Releases](https://img.shields.io/github/downloads/2dust/v2rayN/latest/total?logo=github)](https://github.com/2dust/v2rayN/releases)
 [![Chat on Telegram](https://img.shields.io/badge/Chat%20on-Telegram-brightgreen.svg)](https://t.me/v2rayn)
 
-
 ## How to use
 
 Read the [Wiki](https://github.com/2dust/v2rayN/wiki) for details.
 
 ## Telegram Channel
+
 [github_2dust](https://t.me/github_2dust)