update docs for crazywhalecc/static-php-cli#375

Author: crazywhalecc

docs/en/guide/manual-build.md

@@ -148,6 +148,9 @@ bin/spc download --for-libs=liblz4,libevent --without-suggestions
 
 # When downloading sources, ignore some source caches (always force download, e.g. switching PHP version)
 bin/spc download --for-extensions=curl,pcntl,xml --ignore-cache-sources=php-src --with-php=8.3
+
+# Set retry times (default is 0)
+bin/spc download --all --retry=2
 ```
 
 If the network in your area is not good, or the speed of downloading the dependency package is too slow, 

docs/zh/guide/manual-build.md

@@ -131,6 +131,9 @@ bin/spc download --clean
 
 # 仅下载指定的资源（使用资源名）
 bin/spc download php-src,micro,zstd,ext-zstd
+
+# 设置重试次数
+bin/spc download --all --retry=2
 ```
 
 如果你所在地区的网络不好，或者下载依赖包速度过于缓慢，可以从 GitHub Action 下载每周定时打包的 `download.zip`，并使用命令直接使用 zip 压缩包作为依赖。