[chinese/bash] A wrong code

At the begining of if part, the `-ne` should be `!=` for string compare.

Start with the Chinese Bash tutorial referenced by the issue tag (`chinese/bash`) and open the corresponding markdown lesson file. Find the initial `if` example using `-ne`, and confirm it should be changed to `!=` for string comparison. Since this is docs-only, there are no explicit tests to run; the issue is done when the snippet in that page uses the corrected operator and formatting remains intact.

由索引模型根据 Issue 内容生成。