docs(example-pkg): 将注释和用户界面文本从中文翻译为英文

将示例包的注释和用户界面文本从中文翻译为英文，以提高国际兼容性。修改包括命令补全描述、程序标题格式和用户指南文本。

data/computercraft/lua/rom/packages/example-pkg/1.0.0/completions/example.lua

@@ -3,7 +3,7 @@
 local shell = require('shell')
 local completion = require('completion')
 
--- 为example命令设置补全
+-- Set up completion for example command
 shell.setCompletionFunction('example', completion.build({
   -- 这里可以添加example命令的补全逻辑
   completion.choice{'--help', '-h'}

data/computercraft/lua/rom/packages/example-pkg/1.0.0/programs/example.lua

@@ -1,5 +1,6 @@
--- 示例包程序
+-- Example Package Program
 local colors = require('colors')
+local term = require('term')
 
 function drawTopBar()
   local w, h = term.getSize()
@@ -7,7 +8,7 @@ function drawTopBar()
   term.setTextColor(colors.white)
   term.setCursorPos(1, 1)
   term.clearLine()
-  local title = "Example Package v1.0.0"
+  local title = "=== Example Package v1.0.0 ==="
   local pos = math.floor((w - #title) / 2) + 1
   term.setCursorPos(pos, 1)
   term.write(title)
@@ -17,12 +18,12 @@ function drawTopBar()
 end
 
 drawTopBar()
-print("\n这是一个示例包，展示了LeonOS包管理器的功能。")
-print("\n使用方法:")
-print("  pkg install example-pkg  - 安装此包")
-print("  pkg remove example-pkg   - 卸载此包")
-print("  pkg list                 - 列出已安装的包")
-print("\n按任意键退出...")
+print("\nThis is an example package that demonstrates the features of LeonOS package manager.")
+print("\nUsage:")
+print("  pkg install example-pkg  - Install this package")
+print("  pkg remove example-pkg   - Uninstall this package")
+print("  pkg list                 - List installed packages")
+print("\nPress any key to exit...")
 os.pullEvent("key")
 term.clear()
 term.setCursorPos(1, 1)