change load chrome extension describe

tools/chromium_extension/README.md

@@ -2,8 +2,8 @@
 
 
 ### 手动安装扩展
-> 1. 下载 [chinese-programmer-wrong-pronunciation](https://github.com/shimohq/chinese-programmer-wrong-pronunciation/archive/refs/heads/master.zip) 然后解压，找到 `extension` 子目录
+> 1. 下载 [chinese-programmer-wrong-pronunciation](https://github.com/shimohq/chinese-programmer-wrong-pronunciation/archive/refs/heads/master.zip) 然后解压，找到 `tools/chromium_extension` 子目录
 > 2. 打开 Chrome，输入: `chrome://extensions/`
 > 3. 勾选 Developer Mode
-> 4. 选择 Load unpacked extension... 然后定位到刚才解压的文件夹里面的 extension 目录，确定
+> 4. 选择 Load unpacked extension... 然后定位到刚才解压的文件夹里面的 `tools/chromium_extension` 目录，确定
 > 5. 这就安装好了，去掉 Developer Mode 勾选。