Add x-cmd to the Command Line Tools list. (#1448)

Added x-cmd to the list, x-cmd is a toolset implemented using posix shell and awk.
It is very small in size and offers many interesting features. Here is a milestone demo: https://x-cmd.com/

**Tools Provided by x-cmd:**
  - [Wrappers for Common Commands (e.g., cd, ip, ps, tar, apt, brew)](https://x-cmd.com/mod/zuz): These wrapped commands are more intelligent and easier to use compared to the native commands.
  - [Lightweight Package Management Tool](https://x-cmd.com/pkg/): We have implemented a lightweight package management tool using shell and awk. Through it, you can quickly obtain most common software tools, such as jq, 7za, bat, nvim, python, node, go, etc.
  - [CLI for Useful Websites (e.g., github.com, cht.sh)](https://x-cmd.com/mod/cht): We have wrapped their APIs using shell and awk for daily use and to obtain corresponding services in scripts.
  - [AI Tools](https://x-cmd.com/mod/openai): We provide CLIs for ChatGPT, Gemini, Jina.ai, etc., and have wrapped corresponding shortcut commands for different application scenarios, such as `@gemini` for chatting with Gemini AI and `@zh` for using AI to translate specified content or command results.

README.md

@@ -446,6 +446,7 @@ Any comments, suggestions? [Let us know!](https://github.com/jaywcjlove/awesome-
 * [ohmyzsh](https://github.com/ohmyzsh/ohmyzsh) - A delightful community-driven framework for managing your zsh configuration. [![Open-Source Software][OSS Icon]](https://github.com/ohmyzsh/ohmyzsh) ![Freeware][Freeware Icon]
 * [xcodes](https://github.com/RobotsAndPencils/xcodes) - A command-line tool to install and switch between multiple versions of Xcode. [![Open-Source Software][OSS Icon] ![Freeware][Freeware Icon]](https://github.com/RobotsAndPencils/xcodes)
 * [xxh](https://github.com/xxh/xxh) - Bring your favorite shell wherever you go through the SSH. [![Open-Source Software][OSS Icon]](https://sourceforge.net/projects/zsh/) ![Freeware][Freeware Icon]
+* [x-cmd](https://github.com/x-cmd/x-cmd) - x-cmd is a vast and interesting collection of tools guided by the Unix philosophy.[![Open-Source Software][OSS Icon]](https://sourceforge.net/projects/zsh/) ![Freeware][Freeware Icon]
 
 ### Frameworks For Hybrid Applications