PDF 手册的属性中标题信息不正确

[shawn0915]

Change Request

This repository is ONLY used to solve problems related to DOCS-CN.
For other issues (TiDB, TiKV, etc), please move to other repositories.

Please answer the following questions before submitting your issue. Thanks!

1. Describe what you find is inappropriate or missing in the existing docs.

如图，PDF手册 （如，https://download.pingcap.org/tidb-stable-zh-manual.pdf ）的属性信息，Title 信息不正确，Author信息缺失，建议补充

另外，generate_pdf.sh 这里建议增加

-V title-meta="TiDB 中文手册" \
-V author-meta="PingCAP Inc." \

2. Describe your suggestion or addition.

3. Provide some reference materials (documents, websites, etc) if you could.

[shawn0915]

this way also would fix the issue (https://github.com/pingcap/docs-cn/pull/16173/files#diff-b9b308a275c973824d1539ce6abf0713e8b960e51d63025432146e25c54b2d89R126)